Police in Armenia have shut down a surprise Kanye West concert after the singer jumped into a lake, prompting hundreds of fans to leap in after him.

West was reaching the end of a free midnight gig in the country’s capital Yerevan overnight when he announced to the huge crowd at Swan Lake he was going to do “something a little different”.

Video of the concert shows the rapper suddenly jump into the water during the song “Good life”.

Delighted fans immediately follow suit and swarm around the star in the water, causing police to call a halt to the shenanigans.

West is visiting Armenia with his wife Kim Kardashian, whose late father was Armenian.

Kardashian later tweeted that it was a “crazy night”.

“Kanye wakes me up & says he's doing a free concert in Yerevan, Armenia! I throw on sweats & we head out!”

“Thousands of people were there! Kanye jumped in swan lake to be closer to the crowd on the other side & so many people jumped in too! It was such an exciting crazy night! So happy I got to rock out with everyone in Armenia on our last night here!!!!”