It's really no surprise that most Hollywood relationships begin on set given how much time actors spend together while making a movie. And based on what we've heard, crushes between co-stars are as commonplace as selfies on Kim Kardashian's Instagram.

While most of these crushes don't lead to long-lasting romances, there are a lucky few who managed to meet their soulmate on a soundstage, such as That '70s Show co-stars, Mila Kunis and Ashton Kutcher.

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"Ashton did my chemistry homework for me," the mother-of-two recalled. And even though she saw him as a big brother in the beginning, all of that changed when the couple shared their first on-screen smooch.

mila kunis ashton kutcher r/r

Ashton and Mila on That ’70s Show.

“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,” she confessed.

The duo didn't get together until 2012, but it didn't take long for either of them to realize they had found 'The One.' "We started dating with the idea we're both never going to get married," Mila previously shared. "A year later, we're like, 'Tomorrow, let's get married.'"

Scroll through the gallery below to see which other celebs have admitted to crushing on co-stars!