'Beyonce was very into it!' Queen B shows she's a Britney Spears fan as she takes Jay Z to watch her Vegas show.

They spend their working lives performing for the entertainment of others.

But for a rare date night, Beyonce and Jay Z took a seat, as they joined the audience at a Britney Spears concert in Las Vegas on Friday night.

Beyonce, who has known Britney for years, seemed delighted to be supporting her old friend, getting into the music as she stood up to dance.

An audience member told MailOnline: 'Beyonce was very into it, she was standing and dancing by herself.' 

Beyonce seemed a particular fan of Britney's hit Piece Of Me, getting to her feet as it started. But, the source added, her husband wasn't quite so impressed.

'Jay Z was grooving but didn't stand,' they said.   For the Vegas show Crazy In Love singer Beyonce made an attempt to blend in.

She wore a black hat over her blonde curls, as she sat next to Jay in the VIP section.

Perhaps Beyonce is thinking of following suit, with her star power likely to pull in huge crowds.

Or perhaps she was simply there to show her support for an old friend. 

Back in 2004 she and Britney starred in a Pepsi advert together, singing We Will Rock You, along with Pink.

And while they certainly couldn't be described as BFFs, it's clear Beyonce remains a fan of her fellow diva.