West Ham have signed Said Benrahma from Brentford in a loan deal that will be made permanent next summer for a reported £25 million ($32m).
The Premier League side were initially aiming to sign the Algerian on a permanent basis but issues in the second part of the winger's medical forced a change in the deal.
The Hammers are said to be paying £5m ($6m) up front to take the 25-year-old for the rest of the season before he joins on full-time.
Benrahma will not be eligible to make his debut against Tottenham on Sunday due to his paperwork not being filed in time.
“I’m very, very happy to be a part of this team. West Ham is a historic club, which has been in the Premier League for a very long time," Benrahma told the club's website.
"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.”
Benrahma scored 27 times in 83 Championship appearances for Brentford and West Ham manager David Moyes is confident the new signing will strengthen his side's attack.
"He is a player who has had a lot of recognition for his performances with Brentford in the Championship," he said. "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. Saïd 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 Saïd 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.”