Strain shows in Khan's voice

Audiences thought Chaka Khan sounded a bit off-key during her performance with rapper Kanye West at the MTV Video Music Awards, and they were right.

The R&B diva is blaming strained vocal chords for her screeching performance at this week's awards show in Miami.

A statement released by her publicist Brit Reece said Khan had to cancel a performance in Park City, Utah, last week because her voice was strained and she was under doctor's orders not to perform. However, she "received a cortisone shot just hours prior to her awards performance to honour her commitment to Kanye West".

Reece said the shot helped a bit, but Khan still struggled through the performance of Through the Wire, which contains a sample of her old hit, Through the Fire.

Khan's voice has been strained because of intense recording for an album due out in October, Reece said. For now, Khan is resting her voice, not speaking.

"She is supposed to perform this weekend in the Bahamas, and as of now she is going to do it. She's resting her chords completely this week."