Less than a month ahead of the 20 year anniversary of American Beauty, Hendricks took to Instagram to reveal that she was involved with the film in an usual way.
The 44-year-old actress shared to her delighted fans that she's featured in the Academy Award winning movie's instantly recognizable poster, which shows a hand holding a rose on a stomach.
"Fun fact.... wait for it...I used to be a model and sometimes a hand model.... this is my hand and another model’s stomach," she captioned a pic of the poster. "....proud to be a part if this film in ANY WAY!!! #americanbeauty"
Celebs were blown away by the fun film history fact, with Elle Fanning exclaiming "IM SHOOK!!!!!!" and Rachel Leigh Cook wondering "What else are you hiding from us??"
Hendricks' former Mad Men co-star January Jones also commented on the post, writing, "This is important. How come I didn't know this?"
Whitney Cummings said that new was "blowing my mind," while Alison Brie simply declared "WHOA."
"Wait.... What?!" Busy Philipps chimed in.
Best known for her role in Mad Men, when ET caught up with the actress at 2016 Golden Globe Awards she discussed what kind of spin-off she'd like to see of the AMC series, which ran from 2007 to 2015.
"Joan and Peggy spin-off -- we fight crime," she joked of her and Elisabeth Moss' characters respectively.
"I miss her every day already," she added of Joan. "The nice thing is, people are still enjoying the show and watching it. So, daily, people come up and say something nice about the show, so I get to still have those memories."