The 29-year-old DJ was meant to be enjoying Daft Punk's 'Random Access Memories' playback party at the iconic London venue on Monday (13.05.13) but he slipped away from the bash on the 69th floor to enjoy some private time with his new pop star girlfriend on the 72nd floor of the skyscraper.
A source told The Sun newspaper: ''They looked more interested in each other than watching the sunset. Rita hung on Calvin's every word and laughed hysterically at almost everything he said. He was lapping it up and seemed to enjoy being the centre of her attention.
''But when people came up and started to notice them, they got a little shy and scurried back downstairs to the party.''
The loved-up couple were joined by Jude Law, Peter Serafinowicz and TV presenter Laura Whitmore at the public party and had the pleasure of the first listen of the French duo's new comeback album before leaving the event hand-in-hand.
The pair - who initially clashed last year when the 'How We Do' hitmaker rejected Calvin's 'Call My Name' track - have become smitten with each other over recent weeks and even flew to Las Vegas together in a private jet to attend the Scottish DJ's gig at the beginning of the month.