Adam Lallana has completed his move to Liverpool.
The 26-year-old has signed a long term contract to join Rickie Lambert in making the move from St Mary’s to Anfield this summer.
Liverpool are understood to have paid a fee of around £23m plus add-ons.
Bournemouth are set to receive a bumper payout of about £5.75m due to the 25 per sell-on clause they insisted upon when allowing Saints to sign Lallana as a 12-year-old. Saints will pocket the remaining £17.25m.
After joining Saints from the Cherries, Lallana rose through the academy ranks to become the club’s captain and a hugely influential player for Saints.
Lallana, who informed Saints of his desire to move to Liverpool this summer, leaves St Mary’s having played more than 250 games for the club, scoring 60 goals in the process.
Lallana said: "It has not sunk in if I'm being honest.
"I'd like to thank everyone at Southampton for what they have done for me; I have been there for the best part of 14 years.
"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."
Lallana, a boyhood Everton fan, added "Watching the run-in towards the end of last season it was unbelievable.
"It got the hairs on the back of my neck standing up just watching the style of football.
"Deep down I was thinking to myself 'One day hopefully I'll be able to play in that team'."
Liverpool boss Brendan Rodgers added: "We are delighted to have secured the services of one of the Premier League's top talents in signing Adam Lallana.
"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.
"We have seen, over the past two seasons in the Barclays Premier League, he has a tactical awareness to adapt to what is required of him and to put the team above his personal ambitions.
"He has leadership skills and personal qualities that make him a special commodity and I am delighted we have acted decisively to make sure he is wearing a Liverpool shirt next season.
"Adam is aware there will be great competition for places at this club and he is hungry to improve further. We are confident he will fit perfectly with the culture we have at Liverpool.
"I'm excited about working with Adam and helping him to progress even further."
Saints released a short statement to say: "Southampton Football Club can confirm that Adam Lallana has completed his transfer to Liverpool.
"The fee received from Liverpool, although undisclosed, will allow the club to further develop the first-team squad for the 2014/2015 season."
- VIDEO - Saints' 8-0 thrashing of Sunderland recreated in Lego!
- Don't miss our special 12-page Sports Pink Saints pull-out celebrating ALL the club's high scoring league wins
- Ex-Saint Crouch aiming for a St Mary's hat-trick
- Saints get a video nasty
- Tributes paid to Saints fan whose life bookended the club's biggest wins
- Koeman wants to make Bertrand deal permanent
- Few changes as Saints face testing time
- Serbia punished over drone incident