Aliens exist and it is possible they are among us on Earth, the first Briton to go into space has said.
Dr Helen Sharman told the Observer Magazine that extra-terrestrial life is bound to be somewhere in the universe.
"Aliens exist, there's no two ways about it," she said, adding that "there must be all sorts of different forms of life" among the billions of stars.
Dr Sharman, 56, made history when she travelled to the Soviet space station Mir in May 1991.
The chemist, who now works at Imperial College, London, added that although aliens may 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".
In the interview, she also highlighted her frustration at being 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."
She said being in space "taught me that it's people, not material goods, which truly matter".
She added: "Up there we had all we needed to survive: the right temperature, food and drink, safety. I gave no thought to the physical items I owned on Earth.
"When we flew over specific parts of the globe, it was always our loved ones we thought of down below us."
Dr Sharman was recognised in the 2018 New Year's honours list and joined the Order of St Michael and St George.