Liverpool have completed the signing of Newcastle full-back Jose Enrique for a reported £6m.
The 25-year-old becomes manager Kenny Dalglish's fifth summer signing.
"This is one of the happiest days of my life. I have come to one of the biggest clubs not just in England, but in the world," said the Spaniard.
Enrique joins Jordan Henderson, Charlie Adam, Alexander Doni and Stewart Downing in moving to Liverpool during the summer.
"I am excited by the new signings - it shows Liverpool's ambition," added Enrique, who has signed a long-term deal.
"They spent a lot of money in January on Andy [Carroll] and Luis Suarez, and this summer they've spent a lot of money on other players.
"You can see they have big ambitions and that's why I came here - because I want to win things and I think I can do that here.
"My ambition is win everything with Liverpool. This year we won't play in the Champions League, so the most important thing is to try and win the league."
Enrique added that Liverpool's illustrious history had played a major part in convincing him to move to Anfield.
"They have won a lot of things, including the Champions League," he said.
"Of course I am looking forward to playing in front of the Kop. Everybody speaks about the fans here and they are amazing. I am looking forward to it. I hope it will be this weekend, but if not I can wait."
Enrique joins Liverpool a little more than 24 hours ahead of their Premier League season opener at home to Sunderland.
The Spaniard, who joined Newcastle from Villarreal in 2007 for £6.3m, was disciplined by United last month after criticising their decision to sell major players, such as Carroll and Kevin Nolan, on his Twitter account.