Southampton and England striker Rickie Lambert has moved to Liverpool for a fee of about £4m plus add-ons.
The 32-year-old is part of England's World Cup squad but had a medical while on international duty and is believed to have signed a two-year deal.
The Liverpool-born forward spent five years at Anfield as a youth player.
"I can't believe it. I've loved this club all my life. I left here 17 years ago and I haven't stopped loving it since," said Lambert.
"I have always dreamt of playing for Liverpool, but I did kind of think the chance of playing for them had gone. I didn't think the chance would come.
"I've been trying to keep it as low-key as possible. Only telling close family.
"My mum and dad shed a few tears when I told them, my mum in particular."
Lambert, who has two goals in four England appearances, scored 14 goals in 39 games for Southampton in the past season.
In all, he has netted 117 times in 235 appearances since joining the south coast club from Bristol Rovers in 2009.
Lambert had two years remaining on his contract with Southampton.
"I know how big Liverpool are - and it means everything to me - but I know what is important," he added in an interview with the Liverpool website.
"I know it's what I do on the pitch and the minutes I play.
"I know that's what matters, and that's what I'll be focused on."
There had been interest in Lambert from other clubs, but it is understood he was only considering Liverpool.
Lambert issued an open letter on the Southampton website in which he thanked the club, the managers he has played under and ex-team-mates during his spell at the St Mary's side.
"The five-year plan when I arrived was to get this club from League One to the top half of the Premier League. Against all the odds we have achieved that," he said.
"Now, under Katharina Liebherr's leadership, the club has the chance for a new plan, a new chapter, and I wish them all the success in the world."
Liverpool are still interested in signing England midfielder Adam Lallana, 26, and Croatia defender Dejan Lovren, 24, from Southampton but they say they would prefer not to conduct "any transfers until the new manager is in place".