Hugh Hefner's son Marston has been arrested after allegedly attacking his Playboy model girlfriend Claire Sinclair.

Cops were reportedly called to the house Marston Hefner shares with Sinclair in Pasadena, California on Sunday night after one of her relatives alerted them to an alleged bust-up.

According to TMZ.com, police officers witnessed visible injuries on model Sinclair, who has been dating Marston on and off since August, 2010.

The son of the publishing mogul admitted they'd gotten into an argument but denied striking her, although Sinclair reportedly claimed he had punched and kicked her and prevented her from leaving the property.

Marston was arrested for misdemeanor domestic violence and booked. He was later released on $20,000 bail.