Britney Spears has reportedly turned down the chance to make a second guest appearance on Madonna's world tour - because of family commitments.

Spears thrilled fans at Los Angeles' Dodgers Stadium last week by joining the superstar onstage for a rendition of Human Nature.

And the Toxic hitmaker was reportedly set to perform with the Material Girl a second time when the Sticky + Sweet tour hits Miami, Florida on 26 November.

However, she is said to have scrapped the plans after she was granted custody of her two sons, Jayden James, two, and Sean Preston, three, in the days leading up to the Thanksgiving holiday on 27 November.

A source tells Sunonline.co.uk, "Britney had always agreed to perform in Miami but her circumstances have changed over the past couple of months.

"She and Kevin (Federline, ex-husband) are getting along fine now, Britney will have Jayden and Sean just before the holiday and Kevin will spend Thanksgiving day with them."

Spears is due to fly to France after Thanksgiving to appear on French TV talent show Star Academy on 28 November