Taty Castellanos West Ham debut date, shirt number, contract length revealed as £25m transfer is confirmed

West Ham United have announced the signing of forward Valentin Castellanos from Serie A side Lazio.

The 27-year-old has put pen to paper on a four-and-a-half year contract at the London Stadium with the option for a further year and joins the Hammers for a fee believed to be around €29m (£25m) plus add-ons.

Castellanos will wear the No.11 shirt for West Ham which was vacated by Niclas Fullkrug following confirmation of his loan move to AC Milan that includes an option to make the deal permanent in the summer.

The two-cap Argentina international becomes West Ham’s second signing of the January transfer window after fellow forward Pablo Felipe arrived from Gil Vicente over the weekend for a reported £20m.

Speaking to West Ham’s official website following confirmation of his arrival, Castellanos said: “I'm really happy because it's a very important challenge for me personally and I've come to contribute, to try to help the team as much as I can.

Ready to make his mark ?? pic.twitter.com/3ZXRnoQhuv

— West Ham United (@WestHam) January 5, 2026

Castellanos is “going to give everything” for relegation-threatened West Ham

“Every match is a battle, and I'm here to contribute that, to try to bring that energy, that fighting spirit I have inside, so that every match is as important and as tough as possible.

“I hope to give my all to the fans. I've always defended the jersey of every team with the utmost responsibility, and I want to tell them that I'm going to give everything, to defend this jersey, and obviously, to achieve our goals day after day. That's the most important thing.”

West Ham have confirmed that Castellanos has signed in time to be available to make is debut in Tuesday’s Premier League clash with Nottingham Forest at London Stadium.

The Hammers have also said that Castellanos was identified as a key target by head coach Nuno Espirito Santo, who has come under increased pressure following a disappointing nine-game winless run in the Premier League (D4 L5).

West Ham were beaten 3-0 away against basement club Wolverhampton Wanderers last weekend and their 14-year stay in the top flight is in danger of coming to an end, as they currently sit 18th in the table and four points adrift of safety.

Castellanos and Pablo have been brought in by West Ham to provide a much-needed goal threat to a Hammers side who have scored only 21 goals in 20 Premier League games this season, with only Burnley (20), Nottingham Forest (19) and Wolves (14) scoring fewer.

Who is West Ham’s new signing Castellanos?

Born in the western Argentinian city of Mendoza, Castellanos began his professional career in Chile with Universidad de Chile at the age of 16, two years before joining Uruguayan club Montevideo City Torque where he celebrated promotion from the Segunda Division.

Castellanos then secured a move to MLS outfit New York City FC in 2018 and he made a notable impression in the United States, recording 59 goals and 24 assists in 134 appearances during a successful three-and-a-half-year spell.

After winning the MLS Eastern Conference in 2019, Castellanos celebrated MLS Cup glory in 2021, with the 5ft 10in forward scoring in the final against Portland Timbers before NYCFC won on penalties.

His 19 goals and eight assists saw him win the Golden Boot and be included in the MLS Best XI, before his 17-goal contribution in 25 appearances in 2022 caught the attention of La Liga side Girona.

Castellanos spent the 2022-23 season on loan at Girona, scoring 14 goals in 37 games, before completing a permanent move to Lazio where he contributed to 38 goals (22 goals, 16 assists) in 98 appearances in all competitions, including two Serie A strikes in 11 games this season.