There's nothing weird about a man getting completely nude and jamming out a song for his grandma!  Oh wait, YES THERE IS!  Justin Bieber supposedly did this naked serenade for his grandmother on Canadian Thanksgiving.

Yeah, you're not fooling anyone Justin!  You didn't do this for your grandma you liar!

No man in his right mind thinks, "I know this will check something off my grandma's bucket list".

Your grandma saw your naked butt enough when she was changing your diapers dude!

TMZ obtained the photos, and I feel like less of a man having looked at them.