West Ham have completed the signing of Said Benrahma on a season-long loan from Brentford.
The 25-year-old winger had been due to sign a permanent deal, but complications with his medical prompted West Ham to renegotiate the terms of the transfer.
It is understood West Ham have paid £4m to sign Benrahma on loan and have agreed to make the deal permanent at the end of the season for £21m, plus £5m in add-ons.
The agreement will be subject to further tests on the issues that showed up in his medical.
Manager David Moyes insisted Benrahma had not failed his medical in his news conferences on Friday ahead of the Super Sunday clash against London rivals Tottenham.
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"I'm very, very happy to be a part of this team," Benrahma told the club's website. "West Ham is a historic club, which has been in the Premier League for a very long time. It included and still includes good players. It's a massive club in England.
"I spoke to the manager, so I know exactly what he expects from me. I'll try to meet his expectations on the pitch because he's put faith in me and hopefully I can give it back on the pitch.
"I like this prospect [of playing in the Premier League]! I play football to enjoy myself first and foremost, but it's always enjoyable to know you're joining the most-watched league in the world, so I'm definitely looking forward to showing what I can do."
Moyes added: "I'm delighted to welcome Said to West Ham United. He is a player who has had a lot of recognition for his performances with Brentford in the Championship. There has been a lot of interest shown in him so we are very pleased that he has decided to join us.
"We have been looking to bring in players who are hungry and determined to progress and get better. Said is an exciting talent with a lot of ability and the right qualities, who will complement the other attacking players we have at the club.
"We need to give Said some time to settle in, but the step up to the Premier League is one I am confident he will be able to make. We are really pleased to have him here and looking forward to getting the best out of him."
Benrahma, who will wear the number nine shirt, becomes Moyes' fourth major signing of the summer transfer window following the arrivals of Craig Dawson and Vladimir Coufal as well as the permanent addition of Tomas Soucek.
Sky Sports News understands one of the other difficulties over the transfer was a loyalty bonus that Benrahma believed he was due upon leaving Brentford.
This was not in his contract and Benrahma suggested the club give some money to the many support staff that aided his development during his time at Griffin Park.
It is understood that over 100 staff will benefit from a bonus as a direct result of Benrahma's transfer to West Ham.
Benrahma scored 17 goals in 46 appearances for Brentford last season as they reached the Championship play-off final - suffering a 2-1 defeat to Fulham at Wembley.
The Algeria international began his career in France with Ligue 1 side Nice and made 18 appearances for the first team before moving to Brentford in July 2018.
Benrahma featured 94 times for Brentford, scoring 30 goals during his stint at the west London club.