West Ham boss Sam Allardyce believes the year Andy Carroll spent on loan at Upton Park swayed the England striker's decision to complete a permanent move from Liverpool.
Carroll, 24, was signed for an undisclosed club-record fee by the Hammers yesterday after impressing for large spells of a season-long loan deal at the club last season.
The former Newcastle forward was identified by Allardyce at the start of the summer as his main priority ahead of a second successive Barclays Premier League campaign.
With Carroll's close friend Kevin Nolan captaining West Ham, and relationships struck up during his spell in east London, Allardyce believes the experience of the loan move was invaluable in enticing Carroll to the club.
"Our relationship over the 12 months he was here was key to this deal," he told the club's official website.
"He came to us in a difficult frame of mind and had suffered with injuries but the support the coaching staff and the rest of the boys that work so hard behind the scenes was something he felt very comfortable with in the end.
"He met new team-mates over the year and enjoyed their company and I think that definitely helped him to make the decision to return to West Ham. So not only did the loan pay off by us finishing 10th in our first season back in the Premier League but it has paid off by him choosing us."
Carroll struggled for form at Anfield after completing a £35million switch from Newcastle and was farmed out to West Ham when it became apparent he did not fit into the new approach taken by Liverpool manager Brendan Rodgers.
He has now penned a six-year deal at West Ham, with Allardyce hoping he will lead the line for his side in the coming seasons.
"The size of the contract is a statement of West Ham's belief in Andy and Andy's belief in West Ham," he said.
"We expect him to enhance his reputation even further with West Ham and become one of the major strikers in the country and become an England regular - we hope he will produce for West Ham and England as we prepare to move into the Olympic Stadium in 2016.
"We've acquired a player who was recently the most expensive British player in the history of football. We haven't done it cheaply, but we have definitely done it wisely.
"I told him we will improve him at West Ham while we're at the helm and will give him a chance to become a better player. It will reap rewards for us all. He can now put his experience of Liverpool behind him and show them what they missed by letting him go."
Allardyce guided West Ham to a 10th-placed finish last season after gaining promotion back into the top flight through the play-offs.
Carroll became his third summer acquisition after the free signings of full-back Razvan Rat and goalkeeper Adrian, whilst Stockport youngster Danny Whitehead has also since joined the Hammers.
The 19-year-old scored six times for Stockport last season but could not help them avoid relegation to the Blue Square Bet North, with the Hatters confirming his move to West Ham earlier today.