Aliens exist and it is possible they are already here on Earth, according to the first British astronaut to go into space.
Dr Helen Sharman said she is certain we are not alone in the universe.
Speaking to the Observer Magazine, she said: “Aliens exist, there’s no two ways about it.
“There are so many billions of stars out there in the universe that there must be all sorts of different forms of life.”
Dr Sharman, who has previously said Britain should not fall behind in the space race, said aliens might not be made up of carbon and nitrogen like humans.
“It’s possible they’re here right now and we simply can’t see them,” she said.
Dr Sharman, 56, made history when she participated in a mission to the Soviet modular space station Mir in May 1991.
In the interview, she highlighted how she is often referred to as the first British woman in space, rather than simply the first Briton.
“It’s telling that we would otherwise assume it was a man,” she said.
“When Tim Peake went into space, some people simply forgot about me.
“A man going first would be the norm, so I’m thrilled that I got to upset that order.”