Adam Lallana said he was "over the moon" to be joining Liverpool after he completed his transfer to Anfield from Southampton in a deal believed to be worth up to £25 million.
Lallana, 26, was Liverpool's top transfer target at the start of the summer, as manager Brendan Rodgers set about strengthening his squad ahead of their return to the Champions League after a four-year absence.
But Liverpool have had to be persistent to push the deal through after seeing two initial bids rejected, with the player undergoing a medical over the weekend.
"I'm over the moon for it to be sorted," said Lallana. "I still can't quite believe it. I just can't wait to get started in pre-season and work with the team.
"I'm so excited for the next chapter of my career, coming to a special club like Liverpool. I'm quite humbled and I just can't wait to get started.
"Liverpool have got so much history and after the season they had last season, I can't wait to get started and carry on and build on that. Champions League football is back; everyone is telling me that the atmosphere on Tuesday and Wednesday evenings at Anfield are something special.
"I've been granted my wish to play at such a fantastic club, in Champions League football and competing for Premier League titles. I'm so excited for the next chapter of my career, coming to a special club like Liverpool.
The deal sees Lallana follow former Southampton team-mate Rickie Lambert to Anfield and takes Liverpool's summer spending to £40 million. He becomes Rodgers' third signing, joining Lambert and Germany Under-21 midfielder Emre Can at last season's Premier League runners-up.
"Lambert is up here already and he has been telling me all about it," Lallana said.
"It's great that I can continue my career with him as well. That's a special moment.
"I've spent the last four or five years with him. We've had great careers at Southampton and achieved something special, but we're both thoroughly looking forward to the new challenge."
Lallana leaves Southampton after 14 years at the club, having joined them as a 12-year-old from Bournemouth, who hold a 25% sell-on clause.
The midfielder rose to become Southampton club captain, helping them to return to the Premier League in 2012 after a seven-year absence.
His performances for Southampton also caught the eye of England manager Roy Hodgson and he featured in all three of England's World Cup games in Brazil, coming on as a second-half substitute in the defeats by Italy and Uruguay, and starting in the 0-0 draw with Costa Rica.
Lallana insisted he was looking forward to working with Rodgers having been convinced of his talents by his England team-mates.
"From what I have spoken to him, he seems like a top manager. Everyone compliments him massively and gives him great references. All of the lads at England said that if I did get the chance to work with him then it would help my career in huge ways."
Rodgers was full of praise for his new signing, who scored ten goals last season, labeling him one of the "top talents" in the Premier League.
"We are delighted to have secured the services of one of the Premier League's top talents in signing Adam Lallana," Rodgers said. "What is apparent about Adam is that his character is on a par with his talent.
"He is an exceptional young man and someone who has a love for the game - and, most importantly, a desire to progress and improve.
"Adam is motivated by being the best he can be and being part of something special. We believe he fits right in with what we are trying to do at Liverpool.