The couple got engaged on New Year`s Eve last year, and are currently planning their wedding. Russell turned 35 on June 4, and Katy was determined to make his big day as special as possible. She organised a party for him at the Little Door restaurant in Los Angeles, telling him they were just going for a romantic meal. When they arrived, Russell was amazed to see all his pals waiting for him.
Katy also organised a cake decorated with the Union Jack flag, so the British comedian didn-t get homesick. Then, part way through proceedings, she entered wearing an astronaut-s outfit and presented him with the £100,000 trip into space.
"He was bowled over when he walked into the restaurant and saw she had got all his pals and family together for a surprise party," a source told British newspaper The Sun. "Everyone cheered for the Brit cake, Katy knows how proud he is of his roots."
The trip into space will see Russell board a special craft and climb to 50,000 feet. The rocket will then move towards the edge of the atmosphere, which is when Russell will experience zero gravity.
Katy is currently busy promoting her new album Teenage Dream.
Although she is known for being outspoken - her most well-known track is called I Kissed A Girl - she has blasted Lady Gaga after seeing the video for her new single Alejandro. The promo has caused controversy as it included Catholic imagery, and Gaga dressed as a nun.
"Using blasphemy as entertainment is as cheap as a comedian telling a fart joke," Katy wrote on Twitter.
On a lighter note, she also used the social networking site to announce some exciting news. "THIS JUST IN: I`ll be hosting the 2010 Teen Choice Awards on August 8th!!! TUNE IN TO WATCH THE SHENANIGANS GO OFF!!!! (sic)," she wrote.