During a recent Reddit AMA, the 41-year-old revealed that he and Witherspoon played boyfriend / girlfriend after starring together in the 1992 film Desperate Choices: To Save My Child.
"She was my first actress girlfriend," admitted Sisto. "We had a long distance relationship for a long time. I was so into her. Then she went to Africa to do a movie and I guess I thought she had broken up with me because she didn't call that much, so I moved on and met my ex-wife Marisa. When she returned, I found out that wasn't her intention but i had already gotten involved. Felt badly. She's a great person."
In 1993, at just 18-years-old, the Six Feet Under star married Marisa Ryan, also 18 at the time.
They got divorced in 2002.
He eventually remarried in 2009 and had two children with Addie Lane.
Reese made out pretty well herself, marrying her Intentions costar Ryan Phillippe in 1999 and having two children with him. They divorced in 2007 and Witherspoon had another son with her second husband Jim Toth.
And, in case you're wondering how fond he is of the flick that made him a household name, Jeremy sees the Alicia Silverstone-starrer as a full-on Monet.
"I guess honestly i don't really feel what you might imagine about being in such iconic movie," he wrote. "I wish i did but it's just not as simple as that. I never experienced the movie from that magical perspective of childhood simplicity. Mine was Breakfast Club."