Alexandra Burke, Sarah Harding, Princess Beatrice and Jimmy Carr were among the celebrities who joined the party at the exclusive London venue, part of Branson's Virgin empire.
Lee Ryan failed to gain entry to the event and was turned away by doormen at the Kensington club, according to the Daily Mail.
Guests were treated to a variety of live music, including a DJ set from Boy George and performance from The Overtones. A roller disco and fireworks display rounded off the celebrations.
An auction to raise money for cancer charity Trekstock was also held, with guests bidding for items including a studio session with Mark Ronson and Daniel Merriweather.
Branson said of the event: "I am thrilled that we are celebrating owning The Roof Gardens for 30 years, I can't believe how time flies! This evening has really celebrated everything the venue has to offer and was a fantastic way to say a huge thank you to everyone who has supported us over the years."
Take a look through our gallery of pictures from The Roof Gardens' 30th anniversary party:
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