West Ham have completed the signing of Andy Carroll from Liverpool on a six-year contract for a club-record fee.
The 24-year-old finalised the deal, which is understood to have cost the Hammers £15.5million plus a further £2million in add-ons, after successfully undergoing a medical last night.
Despite the lengthy contract, West Ham have the option to add a further two years if they wish.
Carroll spent last season on loan at Upton Park, scoring seven times in 24 league appearances in a campaign which was dogged by injury.
"It's fantastic for me to be here. I really enjoyed last season, and that shows in me coming back and making it permanent," he told whufc.com.
"The fans, the lads and the club itself has been great to me, and what I wanted to do was come back here and play football.
"Since the end of the season I've had a lot of time to think, I've missed it and that's why I'm back."
The club's website described Carroll as their "marquee signing" who "represents a significant step for the club".
Liverpool sold Carroll at a significant loss, having bought him from Newcastle for a British record £35million on transfer deadline day in January 2011.
He never really fitted in at Anfield despite the best attempts of Kenny Dalglish, the manager who signed him.
Carroll scored 11 times in 58 appearances, but when Dalglish was replaced by Brendan Rodgers last summer it became apparent his chances of regular first-team football would be minimal.
A deal to loan him to West Ham was secured the penultimate day of the transfer window and despite some encouraging performances for the Londoners - which earned him an England recall - it was made clear to the striker Rodgers had not changed his view of him.
"Everybody at Liverpool FC would like to wish Andy all the best for the future," said a statement on liverpoolfc.com.
Carroll finished last season with a heel injury, which ruled him out of the national team's friendlies against the Republic of Ireland and Brazil and could keep him out of the new campaign, which the Hammers start at home to promoted Championship winners Cardiff.
1989: Born January 6 in Gateshead.
2006: April 3 - Scores first goal for Newcastle reserves against local rivals Sunderland.
November 2 - Makes first-team debut in 2-0 UEFA Cup win against Palermo.
2007: July 29 - Scores first senior goal in a pre-season friendly against Juventus.
September 11 - Scores on England Under-19 debut against Belarus.
November - Scores first competitive league goal while on loan with Championship side Preston.
2009: January 10 - Scores first competitive Premier League goal for Newcastle on full home debut against West Ham.
March - Signs a new three-and-a-half-year deal with the Magpies.
August 11 - Makes England Under-21 debut.
October 9 - Scores twice against Macedonia on first Under-21 start.
2010: May - Finishes the season as Newcastle's 19-goal top-scorer as the club win promotion from the Championship at the first attempt.
August 22 - Scores maiden senior hat-trick against Aston Villa.
October 8 - Pens improved five-year deal at St James' Park.
October 18 - Charged with assault of his ex-girlfriend, and granted bail on condition he lives with Newcastle captain Kevin Nolan.
October 21 - Has his car burned out on Nolan's drive.
October 25 - Fined £1,000 after admitting assaulting a man in a nightclub in December 2009.
November 13 - With seven Premier League goals to his name, is named in England squad for friendly international against France.
November 17 - Makes senior England debut in a 2-1 defeat to France at Wembley.
December 13 - Assault charge against Carroll in case involving his ex-girlfriend is dropped, the Crown Prosecution Service deciding there was no realistic prospect of conviction.
2011: January 31 - Newcastle reject two bids in excess of #30million from Liverpool for Carroll. Carroll then hands in a transfer request. Newcastle reluctantly accept a club-record offer from Liverpool, of around £35million, and Carroll completes a switch to Anfield making him the most expensive British player.
March 6 - Makes his Liverpool debut as a substitute in a 3-1 win over Manchester United at Anfield.
April 11 - Scores his first Liverpool goals as he nets twice in a 3-0 win over Manchester City.
September 7 - England manger Fabio Capello complains about Carroll's lifestyle off the pitch claiming that he "needs to drink less than others".
2012: April 13 - Scores the winning goal to send Liverpool to the FA Cup final at the expense of city rivals Everton.
May 5 - After coming on as a substitute in the FA Cup final he scores and has another cleared off the line but Liverpool lose 2-1 to Chelsea.
June 15 - Heads in the opening goal as England beat Sweden 3-2 at Euro 2012.
July 10 - New Liverpool boss Brendan Rodgers admits he is open to the idea of loaning out Carroll.
August 30 - West Ham sign Carroll on a season-long loan deal.
September 1 - Makes his West Ham debut in a 3-0 home victory over Fulham.
November 25 - Scores his first goal for West Ham in 3-1 defeat at Tottenham. He scores a total of seven Premier League goals in 26 league appearances for the Hammers in the 2012-13 season.
2013: May 21 - Liverpool and West Ham agree a reported fee of £15million to make Carroll's transfer to Upton Park permanent, pending the player accepting the move and passing a medical.
June 19 - West Ham sign Carroll from Liverpool on a six-year deal after he passes a medical.