MUMBAI: Singer Susan Boyle, 53, was forced to cancel her American tour due to a sore throat.

The 'Britain's Got Talent' runner-up from 2009 completed the sell-out show at the Balboa Theatre in San Diego, California, the first night of a world tour, but then rushed to see a throat specialist.

After less than 30 minutes on stage, she told fans, "It's typical, I wake up on the first day of the tour and I have a sore throat. Still, us British carry on."

She was told to avoid talking for 36 hours in a bid to let her sore throat heal and was forced to cancel her next gig in Santa Barbara on Thursday night.

A source said, "Susan's suffering from a bad throat infection - she was relieved to get through the concert and did so well to finish her set list on the night."

"The timing could not have been worse for Susan so she has been feeling pretty down over the past few days. She has found it very difficult not to talk - anyone who knows her will understand how much she likes to chat."

"She just wants to get back to her best. She has had the best care possible so hopefully that, plus three days of resting her voice, will achieve that," added the source.