Beaten Australian Open tennis finalist Roger Federer and world number 3 Novak Djokovic are set to play the Halle ATP tournament in June as a warm-up for Wimbledon.
Swiss star Federer, who lost to Rafael Nadal in Melbourne last weekend, won the Halle tournament for the fifth time last year and has signed up along with Serbia's Djokovic, the 2008 Australian Open winner.
Frenchman Jo-Wilfried Tsonga, who lost to Djokovic in the 2008 final in Melbourne, has also agreed to play the June tournament on grass in the German city of Halle.
Another potential crowd-puller will be the appearance of pin-up Anna Kournikova, who will play doubles alongside Germany's Nicholas Kiefer in a special competition to act as a curtain-raiser to the main tournament.
The pair will play against former Wimbledon champion Michael Stich and rising German star Anna-Lena Groenefeld.
