Prince has reportedly demanded an oxygen bar run by three sexy women for his series of London shows.The 'Purple Rain' singer - who started his 21-date residency at London's The O2 arena last night - also requested his Dorchester Hotel suite is decorated completely in black. A source said: "He wants everything to be black, from the curtains, carpets,candles to all the furniture."His entourage have even asked for a black chocolate machine as well as an oxygen bar which will be manned by a team of foxy women."Prince is well-known for his outrageous demands.Earlier this year, it was claimed he asked everyone to avoid eye contact with him when he performed at the BRIT Awards. Meanwhile, it has been claimed the 49-year-old star is dating a set of identical Caribbean twins, his backing vocalists, the exotic duo Twinz.Twinz - who refuse to reveal their real names or ages - won't confirm if their intimate on stage relationship with Prince continues once the show is over.The stunning singers said teasingly: "Prince is a huge fan of ours. He is someone who likes to have beautiful women around him."They added: "He is a cool cat, always dressed to impress. And he keeps us laughing all the time."