Speculation about whether aliens exist has been rife for decades but British astronaut Dr Helen Sharman has no doubts.
Dr Sharman claims aliens do exist and may already be lurking on Earth – unseen and hidden from us, Daily Mail reported.
In 1991, Dr Sharman made history when she was launched into orbit as part of a Soviet project and spent nearly eight days in space becoming the first British astronaut to enter space.
The spacewoman says that there “must” be other life forms out there.
She beat more than 13 000 other entrants to earn her spot in the project, which was designed to boost London-Moscow relations.
The astronaut told The Observer Magazine that aliens exist and there are “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,” she said.
“Will they be like you and me, made up of carbon and nitrogen? Maybe not. It’s possible they’re here right now and we simply can’t see them.”
According to the BBC, Dr Sharman is a chemist and now works at Imperial College, London.
Dr Sharman also expressed her frustration at being referred to as the first British woman in space.
“I’ve never defined myself by gender, and I continue to do so,” she said.
“People often describe me as the first woman in space, but I was actually the first British person. It’s telling that we’d assume it was a man.”