British physicist and cosmologist Stephen Hawking says he’s space-bound after accepting an invitation from Sir Richard Branson.

Speaking with Good Morning Britain on Monday, Hawking, 75, said the Virgin Galactic owner offered him a seat on Branson’s new spacecraft.

“I can tell you what will make me happy, to travel in space. I have already completed zero-gravity flight which allowed me to float weightless,” Hawking. “I thought no one will take me but Richard Branson has offered me a seat on Virgin Galactic and I said yes immediately. Since that day I haven’t changed my mind.”

In December 2016, Virgin Galactic’s new spaceship successfully completed its first free flight with a glide test over the Mojave Desert.

The spaceship, named Unity, had previously been flown on captive-carry flights in which it remained attached to the wing of the mothership, a specially designed jet name WhiteKnightTwo.

Virgin Galactic’s first spaceship broke apart in 2014 during its fourth rocket-powered test flight when the co-pilot prematurely unlocked a system used for slowing the vehicle during re-entry into the atmosphere. The co-pilot was killed, and the pilot survived.