Naked Justin Bieber bares his bottom and just covers his modesty with a guitar during bizarre prank on his grandmother

Via - Daily Mail 
He's often seen showing off his torso by going shirtless, especially of late.

But Justin Bieber shocked his family when he did the full monty during a bizarre nude prank at his grandmother's house in Toronto during Canadian Thanksgiving back in October 2012.

In photos obtained by TMZ, the 19-year-old is seen covering his private parts merely with an acoustic guitar, jamming out a naked serenade for his granny, Diane Dale. 

A nude awakening: New pictures have emerged showing Justin Bieber naked and covering his modesty with a guitar during a bizarre nude Thanksgiving prank 

Nude Justin was staying at his grandmother's home in Toronto when the strange incident went down.

According to the website, Justin had been enjoying a break at her home during the holiday and slept in a little too late on Thanksgiving morning.

Finally waking up after hearing family and friends stirring around the house, he thought he'd play a prank on the unsuspecting clan by grabbing his guitar and playing the naked set.

The pop star went right up to his grandmother and started belting out some impromptu lyrics, singing: 'I Loooove you grandmaaaa ... how are youuuu ... helloooo grandma. 

The full monty: The singer bared his bottom whilst serenading his grandmother Diane Dale whilst in the nude 

While his family and friends were laughing, his giggling granny begged the pop star to get back in his room to put some clothes on.

Justin's grandmother Diane recently defended her grandson in an interview with CTV Ottowa.

Speaking about all the attention Justin's actions attract, Diane said: 'It's totally crazy. I feel sorry for Justin all the time because paparazzi pick on him all the time.

'Anybody else's kids have done the same thing but nobody says anything.' 

One of his biggest fans: Justin's grandmother is seen cuddling her shirtless grandson after one of his stage performances two weeks ago

Close: Justin poses with Diane in this Instagram picture from February this year 

She added: 'He's just a 19 year old boy. And before you criticise him, say, what is my 19-year-old boy doing?'

Justin recently caused controvery again after allegedly getting into a nightclub brawl at a Southhampton, New York nightclub.

Wayne Rennalls who claims that Justin and his entourage attacked him on August 3 gave a press conference over the weekend, alleging that the pop singer kicked him during the brawl.

Footage from the night of the altercation did not show Justin involved in the fight, but Wayne, 22, claims that Justin did get physical.

With his clothes on: Justin is seen adjusting his belt during a stage performance earlier this month

He says the fight with Justin and his entourage started after the pop singer became jealous over girls that he wanted to party with.

'Justin Bieber [was] still running his mouth and I took my shirt off to fight,' he said.

'That’s when they all hopped out of the truck and bum-rushed me. They said, "That’s your f*****g a**,’ and the first one came to me, and I put my hands up to fight, to protect myself.'

The alleged brawl comes after a string of incidents where the singer demonstrated 'pop brat' behaviour'.

He has been pictured spitting on fans and urinating in a janitor's mop bucket in the kitchen of a New York night club.

Controversy: Wayne Rennalls alleges that he was assaulted by Justin during a recent brawl in Southhampton, New York