West Ham United completed the signing of Halmstads BK youngster Sead Haksabanovic on Monday.
Haksabanovic, an 18-year-old attacking midfielder, is regarded as one of the more promising young talents in Europe after impressing for the Swedish club.
He had previously had trials with Manchester United, Liverpool, Manchester City and Chelsea but joins the Hammers on a five-year deal.
West Ham did not reveal the fee, but sources told ESPN FC earlier in the day that the clubs had agreed a €3 million (£2.7m) deal.
"I'm really happy to be here -- it's a dream come true," Haksabanovic told the club's website. "West Ham is a big club and it is a nice feeling to have signed.
Welcome to West Ham United, Sead Hakšabanović! ⚒ pic.twitter.com/hYSkUZIatX
— West Ham United (@WestHamUtd) August 7, 2017
"The move happened quite fast -- we heard that they wanted me, so I was interested to hear the plan for me and when I did I was very pleased.
"I am an attacking player, I like to dribble and shoot, but I work hard for the team. I am really looking forward to getting started, I have watched quite a few West Ham games in the Premier League and I can see that they have some great players and great fans.
"Now I just want to get used to being with the team and then hopefully play some games at some point next season."
Haksabanovic played for Sweden's youth sides before switching his allegiances to Montenegro, making his senior debut for them in a World Cup qualifier against Armenia last June.
He has scored five goals in 22 games for Halmstads this season, with his performances bringing him to the attention of a number of clubs across Europe.
Haksabanovic became the second youngest player in Allsvenskan history when he made his debut in April 2015.
Also on Monday, West Ham received special dispensation to play their Carabao Cup second-round tie away from home as the London Stadium will still not be ready to host football matches.