Justin Bieber thought his father's reaction to his nude pictures was hilarious.

Justin Bieber

Justin Bieber

The 21-year-old singer was photographed naked while on holiday in Bora Bora and his dad Jeremy took to Twitter to praise the size of his son's manhood, writing: "@justinbieber what do you feed that thing. #proud daddy (sic)."

Speaking on the Zach Sang & The Gang radio show, Justin said: "I thought it was hilarious. 'What do you feed that thing'. It's such a dad thing to say. When I found out people were hating on him for saying that, I was like, 'Are you kidding me?' What dad wouldn't be proud of that? It's not like he's saying it to an 11-year-old. I'm 21 years old."

However, Justin admitted he was not happy when the pictures were first released online.

He said: "At the end of the day, the photos, they're not terrible. I still felt like I wanted to keep that part for me, you know? ...I felt like it was a little bit of an invasion of privacy. And when I first found out about it, I was like... my heart sank."

While Justin didn't mind his father's tweet, Bette Midler blasted Jeremy's tasteless tweet.

Calling Jeremy a deadbeat dad in a message on her own Twitter page, she wrote: ".@justinbieber's dad tweeted he's proud of his son's penis size. I think the biggest d**k in this situation is the dad who abandoned his son (sic)."