Experiencing your first kiss may have been thrilling, weird or downright gross, but everyone agrees it's an unforgettable rite of passage. Whether you were a kid or much older, the first kiss is one that sticks with you, regardless of the path you choose in life. Even movie stars remember their first kisses. For some, it may have even occurred onscreen. For Mila Kunis, life has come full circle. She recently got engaged to the person who bestowed her first kiss onscreen – her costar on That '70s Show, Ashton Kutcher. She was just 14 at the time and told People magazine in 2001, "I was like, 'Oh, he's so cute, it's the Calvin Klein model!' Then I was like, 'I have to kiss him?' I was so nervous and uncomfortable. I had the biggest crush on him." For Justin Timberlake and Britney Spears, matching denim outfits weren't the only thing they shared – Spears claims Timberlake laid one on her at the tender age of 13. Another Disney darling got started even earlier – on the set of her dad's show, Doc, Miley Cyrus put her tongue to good use on Tyler Posey, her costar.