Rihanna "sings" No Doubt's "Don't Speak" on karaoke (lmao)

This is the moment Rihanna slurrs her way through a boozy karaoke session.

The controversial popstar, 25, grips the microphone and howls a cover of pop classic Don't Speak over the weekend.

At least three security guards were stood in front of the edgy singer to prevent onlookers taking pictures of the stumbling star.

The embarrassing singalong was filmed in the early hours at the Thai Royal bar in Cologne on June 29.

Rihanna, wearing a baseball cap, was joined by a female pal as she pulls dramatic poses and spins around for the shocked onlookers.

The Bajan star - who struggled to keep up with the famous lyrics - later burst into a rendition of Sex on Fire by King of Leon.

A witness says: "She had just ordered some drinks and fries for the table then just decided to get up and sing.

"It was nice to see her having a lot of fun and she was clearly enjoying herself on her time off."