West Ham United have officially signed Lazio striker Castellanos for a transfer fee of €29 million.

West Ham United officially announced on Monday the signing of 27-year-old Argentine striker Tati Castellanos from Lazio. The two sides signed a contract until June 30, 2030, with an option to extend for another year.

The official announcement also confirmed that Castellanos will wear the number 11 jersey for West Ham United. His transfer fee is rumored to be as high as 29 million euros, making him the third most expensive striker signing in West Ham United's history.

Castellanos came through the youth academy of Universidad de Chile and made his first-team debut in the Copa Sudamericana on June 4, 2017. He then played for Montevideo Torque, New York City FC, and Girona, with his most notable performance being his four goals for Girona in a La Liga match against Real Madrid.

Castellanos also played a key role in helping New York City win the 2021 MLS championship, and he himself won the MLS Golden Boot that season with 19 goals.

In July 2023, Castellanos transferred to Lazio for €18.6 million. To date, he has made 98 appearances for Lazio, scoring 22 goals and providing 16 assists.

After completing the transfer, Castellanos said: "I am very happy because this is an extremely important challenge for me personally. I came here to contribute my strength and do my best to help the team."

“Every match is a battle,” he added. “I will bring my fighting spirit and energy to the field, making every match as important and challenging as possible.”

“I want to give my all for the fans. Wherever I am, I will always defend this jersey with a high sense of responsibility. I want to tell everyone: I will do everything I can to defend the West Ham jersey and continue to work towards our goals – that’s the most important thing.”