Jennifer Garner is the life of the party while working on set: Watch the actress's wholesome BTS moment

Boss's Day is typically celebrated on October 16 in the United States. Jennifer Garner's assistant, Maureen Grosser, marked the occasion with a heartwarming behind-the-scenes moment featuring Garner while she was working on the set of Deadpool 3 (Deadpool & Wolverine),  released in the summer of 2024.

Grosser, affectionately known as Mo, took to social media to share a video of Jennifer in her Elektra Natchios costume. While everyone around Garner seemed focused on their duties, Mo captured the mom of three dancing and goofing around before going back to her action takes. 

© Matt Winkelmeyer

"A sneak peek at what I'm working with. 🙄🤣♥️ Happy Boss' Day, JG!" Mo wrote on Instagram alongside the funny video. Fans immediately flooded the comments section, praising Jennifer for her bubbly, down-to-earth personality. "Literally the coolest and most realistic celebrity ever... just love her," a person wrote under the video. 

"She lights up the room in all that she does. I think she's the most authentic and beautiful inside and out of all celebrities," a second added. While a third assured: "This is epic lol she breaks out in dance then gets into ninja mode 🥷🏻😹."

Jennifer and Mo have a longtime working relationship. In 2020, Garner honored her on social media with a beautiful post about how impactful Mo is in her life. "On my good days, people ask if we're sisters, but more often than I care to admit—the assumption is mother/daughter. We aren't actually related —but I'll claim her. For seven years, Maureen Grosser has planned my life, been my constant travel buddy (Mo wouldn't miss a Save the Children site visit for anything), helped me look organized (🙅🏻‍♀️), and competent at things like SignupGenius(🙅🏻‍♀️), and, most of all, this very platform," Jennifer revealed.

© Bellocqimages/Bauer-Griffin

"People ask what social media company I use—well, I sit in the excellent company of @mogrosser, noodling on ideas, and edits, and captions, playing to our morphed-into-one funny bone," she joked. 

Adding, "Mo isn't one to want attention, but she's in lockup with me at my crazy house, and it's her birthday. Plus, it's time I post something without her approval for crying out loud. Happy birthday, Mosie; we are lucky to have you here with us today and always. We love you. ♥️🎈🎉♥️"

Grosser never misses a beat when it comes to celebrating Boss Day. In 2022, she surprised the actress with a fanny pack filled with Garner's favorite things, including Sparkling Water. 

In the video, Mo listed eight of the "Things Jen always asks for, " including, but not limited to, Spearmint gum, breath mints, pens, chocolate, Once Upon a Farm blends, peach-flavored Waterloo Sparkling Water, reading glasses, and Airpods.

Mo also surprised Jennifer by wearing printed loungewear and socks with the actress's face.