Most people instantly recognize (and bow down to) Justin Bieber.

But not 71-year-old legendary Rolling Stones guitarist and singer Keith Richards, according to a Wednesday report from UsWeekly.

During a chance encounter during a vacation in the Turks And Caicos over New Year's, the Pirates Of The Caribbean: On Stranger Tides star not only failed to put a name to the 20-year-old Believe star's face, he also called him a 'wannabe.'

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Not impressed: Keith Richards (right) was not amused when he ran into Justin Bieber at a beach bar in the Turks And Caicos during a New Year's holiday, according to UsWeekly

Once the diminutive Canadian star walked into the 'tiny beach bar' on the luxurious Parrot Cay island, Richards took notice of him.

A source told the weekly, 'There was an old guy throwing back drinks who said, "Who the f*** are you?"' to the star.

When the 20-year-old pop sensation shot back, 'I don't know, who the f*** are you?' the British rocker became 'amused,' it was claimed.

He sure likes to flaunt his body: The 20-year-old's face has been everywhere these days thanks to his new Calvin Klein underwear ad campaign

A beloved musician: Richards has made a fortune playing with Mick Jagger for The Rolling Stones

He has quite the resume: The 71-year-old has co-starred with Johnny Depp in the Pirate movies

According to an eyewitness, Keith said, 'You're a man, I respect that.' Then the rocker walked away, it was alleged.

Richards calls Johnny Depp, his Pirates co-star, one of his best friends, as well as his Stones band mate Mick Jagger, so it's hard to imagine he would find interest in such a newcomer as Bieber.

But still the weekly insisted Keith called the Beauty And A Beat singer over to have a drink with him.

When Bieber learned that 'old guy' was Keith, he said 'Oh s***. That was Keith Richards?'

'Justin tried to bro down with him,' said the source. But Richards was 'unimpressed.'

The guitar genius then said, 'Let's get one thing straight. You're a wannabe.'

The weekly's source still claimed the ex-boyfriend of Selena Gomez was 'delighted' by the meeting because the two 'swapped numbers.'