Ashton Kutcher Ashton Kutcher

And you thought Charlie Sheen was out there.

Ashton Kutcher has signed up to go to space as the 500th "astronaut" of Sir Richard Branson's forthcoming Virgin Galactic's SpaceShipTwo rocket plane, the billionaire founder announced on his blog Monday.

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"I gave Ashton a quick call to congratulate and welcome him," Branson wrote. "He is as thrilled as we are at the prospect of being among the first to cross the final frontier (and back!) with us and to experience the magic of space for himself."No word yet on a launch date. The SpaceShipTwo, aka the VSS Enterprise, is currently in the final stages of an "exhaustive" test flight program, Branson wrote.

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According to MSNBC, the Two and a Half Men star shelled out the standard $200,000 fare for the ride, which will shuttle passengers 50,000 feet into space. Other celebrities reportedly on the flight list are Tom Hanks, Katy Perry, Brad Pitt and Angelina Jolie, who have also paid their own way, and Stephen Hawking, who is getting a free ride courtesy of Branson. Beyonce and Jay-Z are said to be considering joining them on board, MSNBC says."Ashton is joining a fast expanding group of true pioneers who are on their way to a life changing experience and a place in the history books," Branson continued. "It's great to have him on board."What do you think of this space oddity? And why hasn't Lance Bass signed up yet?!