Lady Gaga went and got all naked on stage at London nightclub G-A-Y on Saturday night.

Yep, you read that right.

Mother Monster, who was left furious after airport staff stopped her taking her dog on a plane recently, was dressed in a weird white ethereal smock-dress-thing when she started performing her new ARTPOP single, Venus, to the jolly clubbing crowd.

And everyone was having a lovely time, until, well, something unusual happened.

The Lady, 27, lifted up her smock and pulled down her knickers, flashing her private bits to her dumbfounded fans.

Then the song finished and Gaga decided to take off her white smock-dress-thing (which we guess might be some sort of Halloween outfit) and flaunt the rest of her naked body to the entire world (well, the world of G-A-Y, who quickly took to Facebook and Twitter to tell everyone else).

(Image: Haus_ARTPOP/twitter)

Once totally starkers, the frizzy-haired singer paused and flaunted her curves before making her way slowly (and ever-so dramatically) off-stage, leaving shocked fans with nothing else to look at other than her bare behind.

One very unfortunate man got stuck in FRONT of her and didn't know where to look as the singer sloped towards him, her arms flailing wildly above her.

Little Britain star Matt Lucas was at the gig and tweeted: "Just saw Lady Gaga do a surprise set at G-A-Y. She got her arse out & showed her vagina. All agreed it was impressive but we're staying gay."

And following the gig, Gaga tweeted: "Had an amazing night tonight at G-A-Y in London, after all these years you continue to inspire me. Can't wait for X-Factor tomorrow night!"

We can't help wondering if Lady Gaga will go all Lady Godiva on us live on the X Factor this evening.

We kind of doubt it. But with Gaga, nothing surprises us anymore...