The initial six-month loan deal has the option for further three-years.
Paulista gave his first interview to West Ham TV and revealed how happy he was to move to the UK to compete in the Premier League.
“I am really happy to be here at West Ham United.”
“Everyone has been very kind to me since I have been at the club this week. I think I can do my best here and I am coming to England to prove to everyone that I am one of the best strikers in Brazil and to get better and better.
“I am strong, I am a fighter and I can score with both feet. I run a lot on the pitch and I can play as either as first or second striker.”