Ariana Grande's brother Frankie has upset the family of fellow U.S. Big Brother contestant Victoria Rafaeli by joking about taking her virginity.

During a livestream on Saturday (30Aug14), Frankie Grande told two male houseguests they should "double team" Victoria and "take all her virginities".

The gag didn't go down well with Rafaeli's mother, who is now demanding an apology.

She tells Tmz.com she understood that Grande was joking but still feels her daughter has become a "target for rape".

The worried mum says, "I want Frankie to imagine people saying this stuff about his sister and see if he thinks it's funny."