Liverpool have sealed one of the shock signings of the summer after confirming Mario Balotelli's arrival from AC Milan.

The 24-year-old has agreed a “long-term deal” according to the club, but will not be registered in time to play against his former side Manchester City.

The Italy striker tweeted the news of his signing minutes ahead of the official club announcement, saying: “YNWA! COME ON LIVERPOOL!”

The club said in a statement: "Liverpool can confirm they have completed the signing of Italy striker Mario Balotelli, subject to registration.

“The 24-year-old sealed his switch to Anfield from AC Milan after passing a medical and agreeing a long-term deal to become the Reds’ ninth signing of the summer so far.”

B alotelli, who was photographed practising on a pitch at Melwood wearing a Liverpool training top, will wear number 45.

The striker told www.liverpoolfc.com that it was a “mistake” to leave England 18 months ago.

“I’m happy to be back because I left England and it was a mistake,” he said. “I wanted to go to Italy but I realised it was a mistake.”

He added: “English football is generally better. English football is beautiful.”

Balotelli is not eligible to play against City but will be watching from the stands at the Etihad Stadium tonight.

“I’m going to be watching the game. I would love to play but I can’t, so I’ll support them from the stand.”

Balotelli has had a colourful career for Inter Milan, Manchester City and AC Milan, as well as with the Italy national side, and has often fallen out with his managers.

However, Liverpool boss Brendan Rodgers today insisted: “This transfer represents outstanding value for the club. Mario is a world-class talent.”

He added: “There is no doubting Mario’s ability; he is a world class talent and someone who, for such a young age, has vast experience of playing at the very highest level.”