Sources close to the family say Tommy Lee's son Brandon, 21, was sticking up for his mom, Pamela Anderson, when he punched out his dad. On Monday, the Mötley Crüe drummer criticized his former wife on Twitter after she brought up his 1998 arrest for spousal battery during an interview with Piers Morgan. The tweet precipitated a fight in which Tommy claims Brandon punched him in the face, leaving him bloodied. But according to TMZ, Brandon struck his father, who lunged at him, in self-defense. Tommy has contradicted the website’s report, claiming on Twitter that: “My [fiancée] and I were in bed when my son busted into the room and assaulted me. I asked him to leave the house and he knocked me unconscious. He ran away from the police. THAT’S the truth.” Tommy says he plans to press charges.