West Ham completed the signing of Mexico striker Javier "Chicharito" Hernandez from Bayer Leverkusen on Monday.
Hernandez, who spent five years at Manchester United before leaving the Premier League in 2015, was entering the final year of his contract with the Bundesliga club. The teams confirmed last week that a deal had been agreed.
The 29-year-old has now signed a three-year deal after the clubs sealed a transfer worth £16 million, West Ham confirmed. He will join up with his new teammates in Germany in the coming days.
"I am very happy to join West Ham United," Hernandez told the club's website. "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 an 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 157 appearances for United before moving on to Leverkusen, where he netted 39 times in 76 games. He also spent the 2014-15 season on loan at Real Madrid from United, hitting nine goals in 33 matches for the Spanish side.
Hernandez becomes West Ham's fourth signing of the summer following the arrivals of Marko Arnautovic on a club-record fee from Stoke, Pablo Zabaleta on a free transfer and Joe Hart on loan from Manchester City.
Hammers joint-chairman David Sullivan said: "We are delighted to welcome Javier as the latest fantastic addition to the West Ham United squad.
"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, LaLiga 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."