The woman was in Astoria nightclub on Guildhall Walk when she was attacked at some point between 2am and 3am.
She was helped by staff, the venue has assisted in the police investigation, and she is now being supported by specialist officers.
As part of the investigation 24 year-old Ethan Barr of Mallings Drive in Bearsted has been charged with rape.
He was remanded to appear at Southampton Magistrates Court on Monday 2 May where he was further remanded to next appear in court on Monday 30 May.
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