The soprano had been training for the mission for several months
Sarah Brightman has "postponed" her plans to visit the International Space Station, a trip that was estimated to cost over £30million.
Brightman said that "personal family reasons" were behind the decision to withdraw from the upcoming expedition, for which she has been training since January.
Eric Anderson, chairman of Space Adventures Ltd, the company behind the trip, said: "Since 2012, Sarah has shared her story of a lifelong dream to fly to space. Her international fame as the world’s best-selling soprano has enabled her message to circle the globe, inspiring others to pursue their own dreams."
Brightman, best known for her collaborations with former husband Andrew Lloyd Webber, including The Phantom of the Opera, announced her intention to travel into space several years ago.
Anderson added: "We've seen firsthand her dedication to every aspect of her spaceflight training and to date, has passed all of her training and medical tests. We applaud her determination and we'll continue to support her as she pursues a future spaceflight opportunity."