The Belgian midfielder emerged as a top transfer target for the Hammers ahead of their first Championship campaign for 14 years as they seek an immediate return to the Premier League.

However, Standard Sport understands that a deal worth potentially in excess of £25million if add-ons are met has now been agreed between the two clubs.

The initial fee is reported as £22m, which would set a new Championship record following Burnley’s obligation to sign Benfica loanee Florentino Luis permanently for £20.8m in July, with the Portuguese midfielder then sold to Ipswich.

Engels - who was the subject of multiple bids from Nottingham Forest in January - is believed to have travelled to London on Friday in order to undergo a medical and sign a long-term contract.

Martin O’Neill, the Celtic manager, confirmed that Engels was closing in on a move to east London ahead of his side’s Premier Sports Cup second-round tie against Dundee United.

“I would imagine that he’s probably at this minute doing the medical,” O’Neill said.

“West Ham wanted him to be available for the opening day of the season. Naturally disappointed, really, that he’s leaving the football club, he’s done very well for us.

“And it’s hard to dissuade him of that. If it hadn’t come up, I think he’d have been happy. Even though the offer came in very late from Nottingham Forest in January, he never moaned about it at all.

“So it’s an opportunity for him and it’s really hard for him to turn it down.”

West Ham are stepping up their bid for further new additions ahead of the September 1 transfer deadline, having endured a slow start to their summer business following relegation from the Premier League on the final day of last season.

The club banked over £150m from the sales of Mateus Fernandes, Crysencio Summerville and Freddie Potts, who joined Tottenham, Al-Hilal and Club Brugge respectively.

Manager Nuno Espirito Santo will value Engels’ versatility and ability to play in central midfield, out wide or at full-back.

He scored 17 goals and provided 22 assists in 100 total appearances across all competitions for Celtic after joining from German club Augsburg as their then record signing in an £11m deal in 2024, winning two Scottish Premiership titles as well as both domestic cups.

Engels began his career with Club Brugge and has earned four senior international caps for Belgium, though was not selected in their World Cup squad this summer.