Pop star Beyonce Knowles narrowly escaped serious injury after her car door was ripped off by a taxi as she stepped onto a busy London street.

The Crazy in Love singer opened the door of her Mercedes after deciding to pop into top store Harrods en route to a restaurant in the UK capital's Knightsbridge area.

Shoppers looked on in horror as the taxi collided with the car's door, ripping it off its hinges and missing Beyonce by just a matter of centimetres.

The singer, who was travelling with her hip-hop mogul husband Jay-Z, looked visibly shaken after the incident. "It was terrifying to watch.

It all happened so quickly, the taxi came out of nowhere," a source said. "She seemed very shaken and was lucky to be alive. A couple of seconds difference and God knows what could have happened," the source added.

Beyonce, 28, and Jay-Z, 40, were on their way to a meal at Japanese eatery Zuma when the singer decided to make her impromptu stop.

After the accident, the couple were forced to leave the damaged car and were sent a replacement to take them to the restaurant. She was later seen looking happy and relaxed after leaving Zuma with Jay-Z.