Lionel Messi said on Wednesday he was delighted to have signed for French club Paris St Germain and that he was ready to help the team clinch their first ever Champions League title.

The Argentinean forward had agreed to stay at former club Barcelona after his deal expired at the end of June, only for the Spanish club to admit they could no longer afford him last week, Reuters reported.

He signed a two year deal with an option for a third with the Parisians on Tuesday.

"That's why I am here. It's an ambitious club," Messi, who will wear the No. 30 jersey - which was his first squad number in senior football at Barcelona in 2006, told a news conference.

"You can see they're ready to fight for everything.

"My dream is to win another Champions League, and I think this is the ideal place to be to do that."

The Argentine conceded he did not know when he would be able to make his debut given he has not played since winning the Copa America with his country last month. Reuters reported.

"I'm coming back from holiday. I need a bit of a pre-season and get myself going. Hopefully debuting can be soon but I can't give you a date. It's up to the coaches."

FAN CRAZE

Eyebrows were raised as to how PSG could afford to sign Messi within UEFA's Financial Fair Play (FFP) regulations. However, club chairman and CEO Nasser Al-Khelaifi, who sat alongside Messi, insisted the deal was well within their economic scope.

"We are always attentive to Financial Fair Play. It's the first thing we check with the commercial, financial and legal people to see if we can do it before signing someone," he said.

"I think the media need to focus on the positives and not just the negatives of these moves, but what positives he brings. He's an unbelievable asset to the club."

Al-Khelaifi's point was backed up by thousands of excited fans who had gathered outside the Parc des Princes stadium in Paris, banging on drums, waving flags and chanting Messi's name, Reuters reported.

"My arrival here was both surprising and crazy," Messi said.

"It was the icing on the cake as if I needed any more convincing. I'm grateful to the fans, it was crazy to see people on the streets in Paris without the deal even being done last week. I was stunned."

Local fan Nelson Dross, 17, told Reuters: "Why do I love him? Because he makes us dream. He's a magician, a genius."

"He's the best player in the world," Sofiane Achi, 19, said. "We want that he wins the Champions League with PSG."

NEW CHALLENGE

Messi on Sunday wept as he told Barcelona fans he was leaving his childhood club, and admitted that while he is sad, he is looking forward to the new challenge and hoped they would understand his decision making.

"I'll always be thankful to Barca and their fans. I went there as a boy, and we had some good and bad times," he said.

"The Barca fans knew I'd join a good club, fighting for the Champions League, because they know me, I like to win, I'm a winner and I want to carry on doing that.

"I don't doubt that PSG's objectives is to win and grow. It would be nice on the one hand to face them (Barcelona) in the Champions League, especially with fans, but on the other strange to go back to my home in another team's shirt - but that's football."