Cape Town - West Ham confirmed the signing of former Manchester United striker Javier Hernandez for £16m from Bayer Leverkusen late on Monday.
The Mexico international arrived in London on Monday for a medical ahead of the move.
Sky Sports News reported that the 29-year-old signed a three-year contract worth a reported £140,000 a week - making him the club’s highest paid player.
"I am very happy to join West Ham United," Hernandez said.
"For me, the Premier League is the best league in the world and when the opportunity came, I was desperate to sign for this club.
"It was not a difficult decision. West Ham is a historic club, and very ambitious - this summer you can see with the players signed that they are looking to have a very good season.
"I've had three fantastic years playing in Spain and Germany, but England was really the first big chapter in my career and I am so happy to be back.
"I am desperate for the season to start and to help the team achieve all their objectives."
Hernandez scored 59 goals in 156 appearances and won two Premier League title with the Old Trafford club before going on loan to Real Madrid in the 2014/15 season.
He then left United for Leverkusen in the summer of 2015, scoring 39 times in 76 matches for the German side.
"We are delighted to welcome Javier as the latest fantastic addition to the West Ham United squad,” West Ham co-chairman David Sullivan said.
"Following the arrivals of Pablo Zabaleta, Joe Hart and Marko Arnautovic, he is another top-class professional who brings great experience and quality to the club.
"He has a proven goalscoring record in the Premier League, La Liga and the Bundesliga, as well in the UEFA Champions League and at international level with Mexico.
"We now have some fantastic options in attacking positions and, like all West Ham fans, I am looking forward to seeing Javier score goals in a claret and blue shirt next season."