Rossi recently returned to action following a broken leg
Seven-time MotoGP world champion Valentino Rossi has confirmed he will leave the Fiat Yamaha team to ride for Ducati for two years from 2011.
Rossi will link up with the team from his native Italy as former world champion Casey Stoner of Australia leaves Ducati to join Honda.
The 31-year-old Rossi finished fifth in Sunday's Czech Grand Prix for Yamaha.
His chances of retaining the world title this year were dealt a blow by a six-week absence with a broken leg.
"It is very difficult to explain in just a few words what my relationship with Yamaha has been in these past seven years," said Rossi.
Working with Valentino is one of the most exciting things for every engineer and its good to know we will have this great opportunity next season
Ducati Corse general director
"Many things have changed since that far-off time in 2004 but especially 'she', my M1, has changed. At that time, she was a poor middle-grid position MotoGP bike, derided by most of the riders and the MotoGP workers.
"Now, after having helped her to grow and improve, you can see her smiling in her garage, courted and admired, treated as the top of her class.
"Now the moment has come to look for new challenges, my work here at Yamaha is finished.
"Unfortunately, even the most beautiful love stories finish, but they leave behind a lot of wonderful memories, like when my M1 and I kissed for the first time at Welkom, when she looked straight into my eyes and told me 'I love you'."
Filippo Preziosi, Ducati Corse general director, said: "Firstly, Valentino is a great fan of motorcycles and so it has always been a pleasure for me to listen to his opinions.
"Until the Valencia GP, he will remain a competitor, one so great that he has always given a special value to our victories, but as soon as he rides the Ducati for the first time we will work together on every single detail that will develop a bike capable of showing his huge talent.
"Working with Valentino is one of the most exciting things for every engineer and it is good to know we will have this great opportunity next season."