West Ham have completed the club-record signing of Eintracht Frankfurt striker Sebastien Haller for a fee reported to be worth an initial £40 million ($50m) plus add-ons.
The 25-year-old has signed a five-year deal with the Irons, with the option for a further year included.
Felipe Anderson was the club's previous record signing having moved from Lazio for £35m ($43m) last year, a month after Issa Diop had broken the Hammers' record with a £22m ($27m) transfer.
"It means a lot [to be the record signing]," Haller said in a statement. "It proves that the club [has] really wanted me for a long time.
"I felt this desire to sign me and I’m really happy to sign, also. it is an ambitious club, a nice club, a nice city and nice fans too.
"For me I can guarantee that I will give 100 per cent for the club because the club has given me this confidence and I will try to give it back every day in every game.
"I will always give 100 per cent and respect the club. I think this is a normal thing and that I can guarantee. I know it’s a big transfer and there is a lot of expectation around me, and I just want to make people proud of this transfer and I will give everything I have."
Haller enjoyed a breakthrough season for Frankfurt last term, scoring 15 goals in 29 league games as Die Adler finished seventh in the Bundesliga off the back of his and Luka Jovic's goals.
The forward had previously picked up a DFB Pokal winners medal in 2018 after he was an 89th-minute substitute as Frankfurt beat Bayern Munich 3-1 in the final.
West Ham's director of football Mario Husillos said: “It is no secret that we have been in the process of identifying a top class striker to add to the squad this summer, and much work has gone on behind the scenes to ensure that we were in a position to act once the right opportunity became available.
“Sebastien is a player we have been watching closely for some time - he has always been a key target and someone who myself, Manuel Pellegrini and David Sullivan were very keen to bring to the football club."
Haller becomes West Ham's fourth signing of the summer following Pablo Fornals and goalkeeping duo Roberto and David Martin.