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Happy birthday Ashton Kutcher (and to your twin, Michael)! The Iowa-born actor rings in his 37th year today. Before his critically acclaimed roles in Dude, Where's My Car, The Butterfly Effect, and as the whimsical Kelso in That '70s Show, Kutcher modeled his abs in fashion campaigns for Abercrombie & Fitch and Calvin Klein. Besides acting and modeling, the Man of Style vet is a venture capitalist and successfully invested in tech companies such as Airbnb, Foursquare, and Skype. Today, the hot dad is married to former co-star Mila Kunis and together welcomed 4-month old, Wyatt Isabelle (we hear Dad is grooming their baby to coach the NFL’s Chicago Bears!). In honor of Ashton Kutcher's birthday, we're taking a look back at more of the hottest celebrity dads in the business.