"Who's the bigger @StarWars fan," she captioned the pic. "The one who bought this awesome shirt at @oldnavy or the one who already owned his own Obi-Wan Kenobi robe?"
Munn, 35, plays superhero Psylocke in the upcoming X-Men: Apocalypse and is a self-confessed sci-fi nerd who wrote the 2010 book Suck It, Wonder Woman! The Misadventures of a Hollywood Geek.
But based on their outfits, her NFL hunk boyfriend, 32, is a bit of a fan boy as well — we bet the pair are counting down the hours till Star Wars: The Force Awakens opens on December 18.
Us Weekly exclusively revealed in early 2014 that the Newsroom alum and the Green Bay Packers quarterback were dating.
"Aaron is different than every other man I've met," Munn told Good Housekeeping in July. "There's so much I could say. Everything a good person can be, he is."
For access to all our exclusive celebrity videos and interviews – Subscribe on YouTube!