Benji Madden plans to warn off his 11-month-old niece's suitors with a shotgun.
The Good Charlotte rocker is fiercely protective of Harlow – his twin brother Joel's daughter with Nicole Richie – and admits he will find it tough when she starts to become interested in boys.
He joked: "I'm going to be keeping a close eye on her. I'll leave the shotgun right by the door."
The 29-year-old rocker added he plans to spend lots of time with Harlow as she grows up, and has already offered to help Joel look after her.
He said: "We're lucky being twins, because Joel can be the good guy and I'll be the bad guy."
Benji – who previously dated Nicole's close friend Paris Hilton - is amazed by Joel and Nicole's parenting skills, and insists they couldn't be better parents.
He revealed: "When they had her, their instincts just kind of came out, and it's amazing to see. They just really put their child above everything."