Singers Robbie Williams and Whitney Houston are set to make their respective comebacks at the O2 Arena in London, England, next year.In case you’ve been living under rock, that’s the same venue where Michael Jackson was set to perform.According to London’s Evening Standard, AEG has been looking for some big names to fill the 23 dates in early 2010 that Jackson was supposed to perform.Both Williams, 35, and Houston, 45, are releasing new albums this year.“Whitney Houston has been on the o2 arena wish-list for a while—she has the voice and hits to sell the arena out several times over,” a source told the Standard.Williams new album, Reality Killed the Video Star, will be released in October.