BRITNEY SPEARS is planning to unveil superstar pal MADONNA as a surprise guest when she kicks off her comeback tour next year.
Brit joined Madonna onstage in Los Angeles last month during the US leg of her Sticky Sweet tour - and Spears wants Madonna to return the favour when she hits the road in New Orleans, Louisiana in March.
The singer's choreographer WADE ROBSON reveals, "I'm choreographing and set-designing her show.
"There's been talk of Madonna making an appearance, and there's so many places we could take that. At this point the main issue is timing."