West Ham have completed the signing of Nikola Vlasic from CSKA Moscow for a reported fee of £25million (€29m).
The 23-year-old has signed a five-year contract with David Moyes' side, the deal having been completed before Tuesday's deadline.
Vlasic scored 33 goals in 108 appearances for CSKA after joining from Hajduk Split, including the winner in a Champions League group game against Real Madrid in October 2018.
The Croatia international, who made four appearances at the Euro 2020 finals, was named Russian Premier League Footballer of the Year in 2020.
"West Ham sent an offer to the club. I said that my wish is to go, because, like I said, I wanted the new challenge," Vlasic told CSKA's website.
"The management understand my position and the clubs negotiated and the transfer happened. I'm grateful for everything that they have done for me in the last three years.
"These three years were beautiful. I've found many friends here: guys, coaches, all the people in the club were like family to me. But I wanted the new step, a chance to prove myself in more competitive league."
The Hammers' deal for Vlasic came amid uncertainty about the future of Jesse Lingard, who was on loan at London Stadium from Manchester United for the second half of last season.
Moyes is said to retain an interest in the attacking midfielder, but Red Devils manager Ole Gunnar Solskjaer is happy to keep the player despite the signings of Jadon Sancho and Cristiano Ronaldo.
