NELLY FURTADO

When: Unknown

The two supposedly hooked up before Ashton gained notoriety on That '70s Show. In 2006, the singer revealed on Australian pop radio that she dated Kutcher way back when. "Before he was really big," she gushed. "Yeah, we kissed like once or twice. It was good."

Smash Probability: Kissing often leads to other things, but Furtado's coy response doesn't lead us to believe she was anything close to a promiscuous girl when the two dated.