Brazilian attacking midfielder Kaka returned to AC Milan on Monday after four unhappy years at Real Madrid during which he went from one of the world's top players to an unhappy, over-priced, injury-prone reserve.
The 31-year-old's dramatic loss of form has also led to him being shelved from Brazil's plans for the 2014 World Cup after he was left out of the Confederations Cup squad this year.
Kaka has been plagued by injuries over the last few years, including one to his left knee shortly after the 2010 World Cup.
He made only 82 league appearances during his time at Real after his 65-million-euro ($85.71-million) move in 2009 and rarely played anything more than a supporting role.
Some 300 supporters were waiting for Kaka outside Linate airport on Monday.
"I'm very happy to be back," he told reporters. "After a difficult period at Madrid, I had been dreaming about a return. I'm not happy that I left in 2009 but these are things that happen in football.
"This is a young team with a lot of great players and I'm happy to have Robinho in the team," he added. "Physically, I'm fine, I haven't had any problems for a while and I want to play.
"I did everything I could for things to work out at Real Madrid and when I realised that there wasn't much space for me, I asked to leave."
He said he still believed that Milan could give him a springboard back to the Brazil squad in time for next year's World Cup.
"I think that Milan can help take me to the World Cup although I want to take one step at a time," said Kaka, who won a World Cup winner's medal with Brazil in 2002 when he was a reserve, and played at the 2006 and 2010 tournaments.
Milan said that Kaka, full name Ricardo Izecson dos Santos Leite, had signed a two-year contract for his return to San Siro.
The announcement of his return came two days after midfielder Kevin-Prince Boateng was surprisingly sold to Bundesliga club Schalke 04.
Kaka's arrival, in a private jet along with chief executive Adriano Galliani, came exactly 10 years after he first set foot at the club as a fresh-faced youngster from Sao Paulo.
During his first six-year spell at the club, Kaka made an immediate impact, scoring 10 goals in his first season as he helped them to land the Serie A title.
He became one of the world's top players with his remarkable burst of speed, vision and ability to shoot from distance with either foot.
He helped Milan to win the Champions League in 2007 and was voted the World Player of the Year the same year.
His Brazil career virtually ended after the 2010 World Cup, when he was a central figure in the team even though he was not fully fit after previous injuries.
He was called up for a pair of friendlies last year and performed promisingly but has not been selected since a 1-1 draw against Russia in March, when he clearly failed to impress new coach Luiz Felipe Scolari.
($1 = 0.7584 euros)