Harry Brook has replaced Jason Roy in England's final 15-man World Cup squad.
Opener Roy was in the provisional squad announced last month but missed the recent one-day internationals against New Zealand because of back spasms.
Brook scored only 37 runs across three matches against the Black Caps but has starred in international cricket over the past year and can bat in both the top and middle order.
Holders England start their campaign by facing New Zealand on 5 October.
The 2023 ICC Men's Cricket World Cup in India features 10 teams and runs until 19 November.
England squad for World Cup: Jos Buttler (captain), Moeen Ali, Gus Atkinson, Jonny Bairstow, Harry Brook, Sam Curran, Liam Livingstone, Dawid Malan, Adil Rashid, Joe Root, Ben Stokes, Reece Topley, David Willey, Mark Wood, Chris Woakes.
Roy was a key part of the victorious 2019 World Cup squad, returning from a hamstring strain during the tournament to make vital scores of 66, 60 and 85 to lead England to the final.
His throw also led to the run out of Martin Guptill that sealed England's dramatic win over New Zealand in the final at Lord's.
The 33-year-old has struggled for form at times since and was not part of the winning 2022 T20 World Cup squad, though did hit two ODI centuries against South Africa and Bangladesh earlier this year.
Roy, who has not played since The Hundred final on 27 August, warmed up before the final ODI against New Zealand on Friday but was omitted from the team again.
His exclusion means Dawid Malan will almost certainly open the batting alongside Jonny Bairstow in India.
Malan, 36, is in sublime form, having hit 54, 96 and 127 as an opener in the 3-1 series victory over New Zealand.
"We have selected a squad we are confident can go to India and win the World Cup," said England selector Luke Wright.
"We are blessed with an incredibly strong group of white-ball players which was underlined by the performances in the series win against a very good New Zealand team.
"The strength of the group has meant that we have had to make some tough decisions on world-class players with Jason Roy missing out and Harry Brook coming into the squad."
Captain Jos Buttler had said Roy could play against Ireland this week to prove his fitness though England have not confirmed whether he will now join that separate 13-man party.
Brook, who has hit 123 runs in his six ODIs to date, was named in that squad for the three-match series against Ireland but will now drop out.
Despite his inexperience in 50-over internationals, Brook, 24, was a surprise omission from the initial squad, given his stunning performances in Tests and T20s since making his England debut last year.
The rest of the squad is unchanged and features eight players from the 2019 side, including Test captain Ben Stokes, who came out of ODI retirement last month to play in the tournament.
Surrey pace bowler Gus Atkinson, 25, is part of the squad after making his ODI debut against New Zealand earlier this month.
Sussex fast bowler Jofra Archer, who bowled the super over in the 2019 final, has not been included because he will not recover from a recurrence of a stress fracture in his elbow in time for the start of the tournament.
England have yet to name their three travelling reserves, though Archer, 28, raised hopes he could go to the World Cup as cover by training with the squad during the New Zealand series.
Leg-spinner Adil Rashid missed the final three ODIs against New Zealand and fast bowler Mark Wood did not play in the series at all because of minor injuries but neither are a doubt for the World Cup.
Chief cricket writer Stephan Shemilt
The England World Cup squad selection has been a strange episode, ever since what turned out to be a provisional party was named back in August.
Back then, Luke Wright said the group he had chosen was the 15 for the World Cup, only for Jos Buttler and coach Matthew Mott to hint at the possibility for changes. Still, even as late as Friday night, Buttler talked about "loyalty" as a selection policy.
However, the sparkling form of Dawid Malan has made the picture clear for England. With Malan demanding a place at the top of the order, Jason Roy was squeezed out of the starting XI.
Once that happened, and with Roy's fitness an issue, the versatility of Harry Brook made him the better option as batting cover for the starting line-up.
It means Roy loses his place in the squad without playing and Brook gets in without making a notable score in the ODIs against New Zealand.
Already out of the T20 side and having handed back his central contract, this could be the end of Roy's international career, one of England's best white-ball batters of all-time.
England have probably found their best World Cup squad, but the path they took to get there has been quite curious.