Javier Hernandez has completed his move from Sevilla to LA Galaxy.
The MLS club agreed a fee of around £7m with Sevilla for the 31-year old.
"I'm arriving with the best club in MLS, so I'm very excited about this. I'm simply ready to finally put the shirt on," Hernandez said.
"I want to achieve a lot of things with the LA Galaxy because that's what prove and show. I signed with this club for [four seasons] so imagine four more stars on this badge. It'll be awesome."
Hernandez left West Ham for Sevilla last summer but has struggled for regular playing time under Julen Lopetegui.
He has been limited to one goal in nine La Liga appearances so far this season and has made only two appearances since November 2.
Hernandez, who is Mexico's all-time leading scorer with 52 goals, will help fill the void up front for LA Galaxy left by Zlatan Ibrahimovic, who left the club for AC Milan following the expiration of his contract in December.
LA Galaxy president Chris Klein said: "The LA Galaxy continue to pursue top talent across the world that will improve our team.
"Javier is one of most successful players in our region and an iconic figure in this community.
"The LA Galaxy have represented Los Angeles and have been the benchmark in Major League Soccer since 1996, and our pursuit of the world's best players for our club will continue to play a part in our success.
"We are excited to add Javier to our club and look forward to him representing the LA Galaxy in our stadium and in the Los Angeles community."
The new MLS season kicks off at the end of February.