Royals and celebrities dressed alike: Who wore it best?

From Lady Gaga channeling Princess Diana to Kate Middleton finding a style match in Sienna Miller, royals around the world both inspire and are inspired by Hollywood's most stylish stars. Scroll through to see how the two worlds have collided to create some of fashion's most glamorous twinning moments. Royals and celebrities alike are loving Orla Kiely's dark floral print with dots – but who wore it first? Kate Middleton wore the Leith x Orla Kiely Margaret Smock Bib Floral Print dress for a February 2018 outing to the National Portrait Gallery in London, left, and Sarah Jessica Parker, center, wore a skirt featuring the print out in New York City in January. The first famous name we spotted wearing the Orla Kiely design, though, was actress and comedian Sandra Bernhard, right, who sported it at Cyndi Lauper's 2017 'Home for the Holidays' concert benefitting the True Colors Fund at Beacon Theatre on December 9, 2017 in NYC.

Talk about a regal look! Black Panther star Danai Gurira, right, looked like a true queen at the premiere of the blockbuster hit in Johannesburg, wearing a gown by The Row and spectacular traditional neckpiece. South African-raised Princess Charlene of Monaco wore a similar look – a green asymmetrical dress with a Zulu necklace – at the IAAF Diamond League Meeting Herculis track and field competition on July 21 in Monaco.

Timeless Chanel is a hit with glamour girls whether in Hollywood or royal circles! Blake Lively, right, was spotted leaving The Whitby Hotel in New York City on October 16, 2017 wearing a spring 2007 haute couture gown by the famed French fashion house. But the dress had been seen before! Princess Grace's daughter Princess Caroline had donned the dress, which was created by good pal Karl Lagerfeld, at the July 2007 Red Cross ball in Monte Carlo, left. The Monegasque Princess's daughter-in-law Beatrice Borromeo also wore the gown just three months before Blake was seen in the design.

In September 2017, Monaco royal Charlotte Casiraghi, center, sweetly dressed down a floral leather Gucci skirt with a black t-shirt and pink shoes at the brand's Milan Fashion Week Spring/Summer 2018 show. Sticking to the rock chick runway look – with a black embellished sweetheart bustier – were The Originals actress Phoebe Tonkin at Entertainment Weekly's annual Comic-Con party in San Diego in July, left, and Canadian artist Petra Collins, right, as she stepped out for the Vanity Fair and Saks Fifth Avenue 2017 International Best-Dressed List party on October 19 in NYC.

Valentino is a hit with royals and the starry set – and also, of course, first ladies! Both Melania Trump, left, and Crown Princess Marie-Chantal of Greece, right, fell in love with this gorgeous Valentino print. The American first lady wore a short version of the A-line dress for a visit to Paris in July 2017, while the Greek royal opted for a floor-sweeping gown to help King Harold and Queen Sonja of Norway celebrate their birthdays in Oslo back in May.

Carole Middleton took style inspiration from her elder daughter Kate for her 2017 Wimbledon appearance, wearing a tiered dress very similar to one the Duchess of Cambridge wore back in September during her royal tour of Canada and identical to the one worn by Peter Phillips' wife Autumn Phillips to Royal Ascot. Carole and Autumn's dress is by British brand Rumour London. Meanwhile Prince William’s wife sported a bespoke long sleeve dress that retailed for over $5,000 from Alexander McQueen’s Resort 2017 collection, which featured a high-neck collar and red broderie anglaise pattern number.

She may not be a royal but this twinning moment deserves an honorable mention! Princess Diana's niece and cousin to Princes William and Harry, Lady Kitty Spencer wore a longer version of this Dolce & Gabbana dress to the Serpentine Galleries Summer Party. Kendall Jenner stuck to a mini version for the Veuve Clicquot Polo Classic earlier in June 2017.

Melania Trump wore the $2,255 Mary Katrantzou colorful dress to the Congressional Picnic on June 22. Sophie Wessex brought the dress along during her March 2017 visit to Malawi.

Crown Princess Mary of Denmark took a page out of Michelle Obama's fashion book for her visit to Stockholm on May 30, 2017. The Danish royal and former first lady, who wore the dress during her visit to Morocco in 2016, chose to leave their hair down and wavy to complement the flowy Altuzarra Winnie dress.

Queen Letizia of Spain, left, and supermodel Karlie Kloss, right, showed that wearing a Stella McCartney gown plus some serious diamonds will always be a winning combination. The Spanish royal wore a red version of the asymmetrical caped dress for King Willem-Alexander of the Netherlands' birthday party in April 2017, while cover girl Karlie wore the look first at the 2017 Oscars.

Here's a dress that has both the 'Vogue' and the royal seal of approval! At the 2017 BAFTAs, the Duchess of Cambridge wore a full-length, off the shoulder version of an Alexander McQueen gown that Anna Wintour's daughter, Bee Shaffer, had donned in 2015. The daughter of American Vogue's editor-in-chief opted for dress with spaghetti straps at the Museum of Modern Art Film Benefit in New York City.

The Spanish royal paired her Carolina Herrera Prince of Wales cut-out dress with nude heels while attending the last day of the 'Woman and disability- We cross borders' International Congress in Avila, Spain in March 2017. The Scandal star opted for black pumps for her Times Talks appearance almost a year earlier in April 2016.

Eagle-eyed style watchers noted that the nude and black lace gown that Queen Letizia wore to the October 2016 Princess of Asturias Awards ceremony in Spain, right, looked just like Nicole Kidman's gorgeous gown at the Omega 'La Nuit Enchantee' gala in Vienna back in 2013. The dresses, though, are by two different designers: Nicole's is by Oscar de la Renta, while the Spanish royal's dress was created by Felipe Varela.

The Duchess of Cambridge looked chic in the Netherlands for her first solo trip abroad in 2016 wearing a periwinkle peplum jacket and matching pencil skirt by Catherine Walker. In 2014, actress Angelina Jolie wore a similar skirt suit by Ralph & Russo to meet Kate's grandmother-in-law, Queen Elizabeth. The Oscar winner looked polish in the pastel-colored ensemble for her audience at Buckingham Palace, where she was presented with the Insignia of an Honorary Dame Commander of the Most Distinguished Order of St. Michael and St. George. Like Kate, the Oscar winner completed her sophisticated look with a low chignon.

Weeks after the Duchess wowed in an off-the-shoulder midi dress by Barbara Casasola for the Art Fund Museum of the Year Award held at the Natural History Museum, Melanie donned the same dress in another shade across the pond for a Hallmark Channel TCA event. While Kate wore her glossy locks down with the frock, the Hollywood actress opted for an elegant updo.

For Kate's private engagement with the Bhutan royals she wore a $1,495 Tory Burch floral mesh gown featuring retro-inspired flowers and side slits. Then, just hours after Kate stunned in the gown, actress Drew Barrymore attended the ASPCA Bergh Ball in New York City wearing the same style. Designer Tory acknowledged the coincidence was funny, telling HELLO!, “I had no idea!”

The Dior darlings rock some of the couture house's finest dotted garments, with the Monaco royal showing off a capped-sleeve creation from the brand's fall 2015 collection while Jennifer shows off her toned arms in a sleeveless variation at the premiere of 'The Hunger Games: Mockingjay - Part 2' in London.

It's hard to decide who wore this silver-and-white Elie Saab design better. Jordan's queen sported the number at the 2007 Bambi Awards, while fashion royalty Diane turned heads at the 64th annual Venice Film Festival.

Check out these belles of the ball! Here, both style icons shine in nude colored gowns with floral embellishments - the monarch at a gala dinner with Japanese royalty and the actress to pick up an Oscar for Blue Jasmine in 2014.

The Queen's granddaughter and the Queen of Pop have both stepped out in this strappy Dolce & Gabbana black gown. Beatrice strutted her stuff in a charity fashion while Madonna kicked up her heels at Vanity Fair's 2007 post-Oscars bash.

The Hollywood actress had fashion fans green with envy as she walked the red carpet at the 2011 Bambi awards in a slinky, plunging number by Elie Saab. The following year at the 2012 Nobel Prize ceremony, Sweden's future queen shimmered in a similar emerald gown, which she paired with a show-stopping tiara.

The purple Atelier Versace gown that Tina wore to the 2016 Oscars is reminiscent of the striking indigo Ralph Lauren gown Charlene wore to a special dinner honoring the American label in 2013.

A little print goes a long way for this stylish duo, though Sienna is much more prone to rocking loud prints than Kate. A few days after the latter made a colourful entrance at the 100 Women in Hedge Funds gala in eye-catching Erdem, actress Sienna embraced the same color scheme in a printed Marc Jacobs gown at the London premiere of her film 'Burnt'.

Both Kirsten, left, and Monaco royal Beatrice Borromeo, right are big fans of Valentino's spring 2016 Roman goddess look, featuring a deep V neckline and belted bodice. Beatrice opted for a silk printed look from the ready-to-wear collection for a fundraiser in Italy, while actress Kirsten wore a velvet haute couture version.

It's no coincidence that the Swedish royal's powder-blue gown looks eerily similar to Chrissy's Oscars ensemble in 2015 - they were both created by master designer Zuhair Murad. The Sports Illustrated model opted for a sexier look complete with plunging neckline and high slit, while Sofia embraced a more modest silhouette to attend a pre-wedding dinner with her now-husband Prince Carl Philip.

With broad shoulders and long, lean physiques, these statuesque blonds definitely know how to work a halter neckline. While the Monegasque royal embraced a ruffled collar at the Princess Grace Awards Gala in 2013, the Hollywood actress opted for a sleeker finish at the 2014 Golden Globes.

Looking oh-so-elegant in off-the-shoulder midnight-blue gowns, these twins are both queens of the red carpet. Princess Mary steppe out at the 2014 Bambi Awards with her husband Crown Prince Frederik while Sarah Paulson attended the 2015 Emmys, where she was nominated for 'American Horror Story'.

These fashionistas know a good Grecian-inspired dress when they see one. The Monaco royal shined in pink Chanel at the 2010 Rose Ball, while Kate dazzled in draped Alice Temperley to celebrate Chopard's 150th anniversary in 2010.

Both Letizia and Julia put their own spin on classic black and white. And while the Spanish queen gave her ensemble a black-tie boost with a sparkling skirt, the actress proved that even a simple strapless dress and crisp white blouse can steal the show at a high-profile event.

Future monarch Victoria's ability to pull off a princess ball gown is in her DNA, but comedienne Sarah Silverman, here in bordeaux Zac Posen, proves that even Hollywood starlets can have royal-worthy moments.

Both Kate and Angelina have elegant dressing down to an art form, something they both achieved in light-blue chiffon gowns with cinched waists and keyhole detailing in the back. Kate slid hers on for the London premiere of 'Spectre', while the mother of six screened her most recent film 'By The Sea' in New York.