SINGER Madonna may be nearly 50, but she is clearly still fighting fit.

The star got up close and personal with Justin Timberlake as they performed a duet in New York.

The former N'Sync singer joined Madonna on stage to perform their No 1 hit Four Minutes as she delighted fans with a special intimate concert at the Roseland Ballroom to celebrate the launch of her album Hard Candy.

It is her 11th album and follows on from Confessions On A Dance Floor, which sold more than 8million copies. And later this year, Madonna, who is married to British film director Guy Ritchie, will embark on a world tour.

The tour, which is expected to start in London on September 11, begins one month after she turns 50.

Huge shows are planned for Australia, Brazil and Argentina. There are also rumours she plans concerts in Dubai and Israel.

Her last world tour, in 2006, became the highest-earning show by a female artist. Around 1.2m people attended 60 shows, making £102.3m.