Former Manchester City academy youngster Martin Samuelsen has joined the Irons on a two-year contract.
The Norwegian teenager was with the former Premier League champions for three years and after impressing at an Upton Park trial landed a deal until 2017 with the option of a further two years.
He told the club website: ‘I’m very pleased to have signed for West Ham United.I’m j ust really looking forward to getting started next season.
‘First of all I want to play well for the U21s and get goals and assists. Overall I want to help the team do well and maybe lift the league title.
Academy boss Terry Westley said: ‘Martin is a very interesting character. He can play as a No 9 or No 10. As a young prodigy at 14, Real Madrid, Chelsea and Manchester City were all trying to sign him.
‘He’s gone through a real growth and development recently. We see the potential in this boy and we’re so pleased that we managed to persuade him to come. He had a number of Italian and German clubs interested in him yet he decided to join us.’