Calvin Harris flew 15,000 miles to spend the night with Rita Ora.

The Scottish DJ reportedly racked up the air miles in a ''desperate'' bid to join the 'Radioactive' singer for her Studio 54-themed 23rd birthday party at London's nightspot The Box club on Tuesday night (23.11.13).

Calvin flew an initial 5,000 miles from Los Angeles to party with Rita and pals until 5am before hopping on another 10,000 mile flight from London to Sydney where he headlined Australia's Stereosonic festival.

A source told The Mirror newspaper: ''Calvin was desperate to see Rita on her birthday, even though their schedules saw them on opposite sides of the globe. So he booked flights to make sure he could spend the whole day with her, flying into London for just 24 hours.''

Rita was reportedly ''delighted'' by the grand gesture from her boyfriend of six-months, who lavished her with expensive gifts including a Playstation 4 games console and a pair of Christian Louboutin shoes.

The source continued: ''They made the most of their time together, staying out until 5am before heading back for an afterparty together, but just hours later he had to get on another flight. Rita was delighted that he made such a special effort for her.''

Rita had thrown a joint bash with her stylist Kyle De'volle at posh restaurant Hakkasan before heading to The Box where she was joined by Kelly Brook and Rizzle Kicks, but her best pal Cara Delevingne did not make an appearance.