Sarah Brightman will perform a song in space later this year.
Sarah Brightman, who is training at Star City near Moscow, is due to blast off on a Russian Soyuz craft on September 1.
She will spend 10 days aboard the International Space Station (ISS), 260 miles above Earth.
Sarah Brightman, 54, said singing in space was a “very different” proposition to performing on Earth.
Speaking at a press conference in central London, Sarah Brightman said her team were trying to work out the technical details of performing on the ISS.
Sarah Brightman said she had been working with her ex-husband Andrew Lord Lloyd-Webber to find a song that “suits the idea of space”.
She recorded the song in New York last week and it will appear on a retrospective of her career, out later this year.
“To sing in microgravity is a very different thing to singing down here,” the singer said.
“We use the Earth to ground ourselves when we sing and the air around us.
“This is going to be very different. I’m trying to find a piece that is beautiful and simple in its message, as well as not complicated to sing.”
Sarah Brightman didn’t want to “promise too much” because of the complexity of the idea.
In 2013, Canadian astronaut Chris Hadfield’s rendition of David Bowie’s Space Oddity from the ISS become a huge YouTube hit.
Sarah Brightman is thought to be paying around $51 million to become the eighth space tourist.
She said she had paid for the trip herself, but could not “contractually” say how much it had cost.
Sarah Brightman will be part of a three-person crew travelling to the ISS. The last space tourist to make the trip was Cirque du Soleil founder Guy Laliberte in 2009.
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