JANUARY JONES

When: 1998-2001

January Jones scooped up Ashton Kutcher right as he began his 8-year run on That '70s Show. They stayed together for three years, during which Kutcher starred in the cult classic stoner comedy Dude, Where's My Car? Their romance fizzled out soon after, though. According to the Mad Men actress, Kutcher wasn't a good boyfriend. "He was not supportive of my acting," Jones told GQ in 2009. "He was like, 'I don't think you're going to be good at this.' So, fuck you!" What a difference a decade makes.

Smash Probability: Three years in Hollywood is a long time, especially when your rise to celebrity status happens seemingly overnight like it did for Ashton in 1998.