Liverpool have signed midfielder Thiago Alcantara from Bayern Munich on a four-year deal for £20m.
The fee for the Spain international, 29, could eventually rise to £25m with bonuses.
"It's an amazing feeling. I was waiting for this moment for a long time and I am very happy to be here," he said.
Thiago will wear the number six shirt at Anfield and becomes the club's second summer signing after Greece left-back Kostas Tsimikas.
He won La Liga twice with Barcelona before a 2013 move to Bayern, where he won the Bundesliga seven times and the Champions League in August.
His arrival at Anfield ends weeks of speculation about whether the Premier League champions would make a stand-out summer signing.
The £20m fee will be paid in instalments over the length of the deal, and up to an additional £5m will be paid based on the Reds' success in the Premier League and Champions League as well as any individual awards earned by Thiago.
"Absolutely great - I'm really happy that it finally worked out and we could just do it," said Liverpool manager Jurgen Klopp.
"I know all the people at Bayern wanted to keep him desperately. That's normal and understandable because he played an important role, in the last season as well.
"He just was ready for a new challenge and he decided for us."
Thiago added: "I must adapt to the team as fast as I can in the situation and the context that we are living right now.
"Everything is more compact and we started a little bit later, but still it is football and I think we have to mix all the big things up, all the good things we have.
"I will help the team in a defensive and offensive [way] and also in a mental aspect."