The 'Two and a Half Men' actor has signed up to be the 500th customer to travel into outer space with Virgin Galactic, Virgin CEO Sir Richard Branson has announced.

Writing on his blog, Richard said:  "I gave Ashton a quick call to congratulate and welcome him. 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."

According to the company's official website, tickets for the trip cost $200,000 but the date of Ashton's space flight has not yet been announced.

The businessman added: "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. It's great to have him on board."

Launched in 2005, Virgin Galactic is set to be the first commercial airline to offer suborbital spaceflights.

Russell Brand is also said to be one of the lucky people going into space after estranged wife Katy Perry bought the ticket for him.