Justin Bieber 'drops 20,000 Euros for private tour of Vatican City... but angers employees as he disrespectfully kicks around a ball'

Two years ago, Justin Bieber was very publicly embarrassed for his obvious lack of education when he referred to the Sistine Chapel as 'the 16th Chapel' on The Late Show With David Letterman.

So with the popstar currently living it up with his father, Jeremy, and his entourage of burly bodyguards in Rome, Italy, he decided to go directly to the source in order to brush up on his history, with the Sistine Chapel among a number of tourist spots visited on Wednesday.

And trust the Biebs to do it in style, reportedly dropping a whopping 20,000 Euros for a private after-hours tour of Vatican City, taking in the Pope's official residence as well as the Vatican Museums.

But while the star's tour may have given him an understanding of Letterman's reference to its elaborate artworks covering the walls and ceilings - which he compared to the star's growing tattoo collection - it seems he's still not up on the protocol.

Not only was the 20-year-old dressed down in very casual attire that left his tattoo sleeves on display, but he reportedly rubbed employees up the wrong way when he disrespectfully began kicking a ball around in the corridors of the historic buildings.

'Where is Goliath ;) #wheninrome': He donned a surly expression on his face as he slipped on a ragged costume for a photo opp, citing the future King of Israel who defeated the huge Philistine warrior in battle