Inter Milan and Portugal midfielder Joao Mario has completed his loan move to West Ham.
Manager David Moyes has been keen to add more creativity to his squad, especially after injuries to Manuel Lanzini and Marko Arnautovic.
Mario, 25, signed for Inter from Sporting Lisbon for £35m in August 2016.
But he failed to make the expected impact as he struggled to adjust to the tactical nature of Serie A.
He has not been helped by the Serie A side’s chaotic managerial situation, having sacked two managers last season and replacing a third in the summer, when Luciano Spalletti took over from Stefano Vecchi.
Moyes said he needs Mario to adapt quickly to the demands of the Premier League.
“My biggest concern is not him as a footballer but getting used to the Premier League, the speed and competitiveness compared to Italy or Portugal,” he said.
“His ability as a footballer is not in question, he’s proved it, and I just hope he can hit the ground running. That’s my only concern.”