It's hard to believe, but it's been 16 years since "13 Going on 30" first hit the big screen.

Mark Ruffalo celebrated the special day by posting a photo of himself and co-star Jennifer Garner from the beloved rom-com to social media along with a "Happy Anniversary" message.

"Remember what the world was like when Razzles were all the rage?" the "Avengers" star, 52, wrote on Thursday, referencing the real-life candy featured in the movie. "Missing that time."

The Gary Winick-directed film follows the story of Jenna Rink (played by Garner), a 13-year-old girl who dreams of being popular. At her birthday party in 1987, Jenna is bullied by a group of mean girls and wishes she was 30 years old. Pretty soon she discovers her wish came true and she is in the year 2004. Jenna must adjust to her new normal and figure out who she truly is.

Ruffalo played the role of Matt Flamhaff, Jenna's childhood best friend and, as most rom-coms go, eventual soulmate. The two have oodles of chemistry in this sweet flick -- look no further than their characters' epic dance routine to Michael Jackson's "Thriller" for proof.