The Love Island star and former X Factor hopeful was targeted by up to eight men while chatting on her phone in Marylebone on Tuesday (14 April).
Bianca, 28, lost her phone in the attack.
She later said: "Beautiful day. Shame it just got ruined by being robbed! Got ambushed by a bunch of lowlifes on bike."
Police released a statement saying: "Police were informed of the theft of a mobile phone, which happened at about 3.45 on Tuesday in Wimpole Road, Marylebone. An appointment has been made to speak to the victim."
Bianca is the stepdaughter of former footballer Paul Gascoigne.
She made a name for herself as the winner of ITV's Love Island back in 2006, and has also appeared on Celebrity Coach Trip and Snog Marry Avoid.
Two years ago, she auditioned for The X Factor with Mary J. Blige's 'I'm Going Down' as her song. Unfortunately, she didn't get through to the next round.
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