Reigning triple World Superbike champion and MotoGP race winner Troy Bayliss, who retired from motorcycle competition last season, will test the Ducati Desmosedici GP9 from May 12-14 at Mugello.

The Australian, who will also be present as a guest of Ducati at this weekend's Monza World Superbike round, will ride the factory's MotoGP machine alongside official test rider Vittoriano Guareschi.

Ducati state that 'the test has been planned for a while and will be repeated during the year at future official sessions of the Test Team'.

Bayliss will contribute towards development of both this year's GP9 and next year's GP10.

Bayliss was a permanent MotoGP rider from 2003-2004 with Ducati then spent 2005 with Honda Pons. He made a one-off race-winning return for the Italian factory at Valencia in 2006 (the last race of the 990cc era).

So far this season, Casey Stoner has taken the carbon-fibre GP9 to first (Qatar), fourth (Motegi) and third (Jerez) places. The 2007 world champion is currently second in the championship, eleven points behind Yamaha's reigning champion Valentino Rossi.

However, as has been the case since Stoner's arrival at Ducati in 2007, the other Desmosedici riders are yet to get close to his performances - with the next best GP9 rider rookie Mika Kallio in eleventh. The Finn, who rides for the satellite Pramac team, has taken a best race finish of eighth.

With the Italian Grand Prix also being held at Mugello later this month, it will be interesting to compare the lap times set by Bayliss with the five regular Ducati riders during the May 29-31 event.

Bayliss, who turned 40 at the end of March, was World Superbike champion in 2001, 2006 and 2008. In addition to his Valencia victory, Bayliss took four third-places in MotoGP with a best championship ranking of sixth, during his debut 2003 season.

Troy has indicated that his future plans will include V8 Supercar racing.