The Crash star - who dated the blonde actress from 1996 to 1998 - admits he was head over heels in love with Diaz.
And Dillon insists it was the Charlie's Angles star who inspired him to be the best actor he could be.
He told Parade magazine: "It's a very powerful thing when you feel that way about somebody. Cameron was a muse for me. I hadn't been in any deep emotional relationships."
The former teen idol, who split from Diaz shortly after they finished shooting There's Something About Mary together in 1998, also hinted that he wanted to have a baby with the actress.
He added: "I sometimes think love is God's way of hoodwinking people into having kids. You fall in love, and all that passion goes into procreating and wanting children. I've felt that need to want to raise a child. It's a creative urge."
Diaz is now dating pop heartthrob Justin Timberlake.