West Ham United are delighted to announce the signing of teenage midfielder Diego Poyet.

The 19-year-old joins the Hammers on a four-year deal following the expiry of his contract at Charlton Athletic, after the two clubs agreed an undisclosed compensation fee for his services.

Poyet burst into the Charlton first team in January 2014, making 23 impressive appearances during the second half of last season to earn the club's Player of the Year award.

The youngster has joined his new team-mates at their pre-season training camp on the French-Swiss border and is looking forward to starting life as a West Ham player.

"I'm very happy to be here. It took me by surprise a little bit and it all happened very quickly," said Poyet. "It's a great Club to be at and I know a few of the boys here already.

"It was a no brainer to sign, I wanted to come out here to the training camp as soon as I could and I'm grateful that they've had me here.

"It's massive to come to a Premier League club. It's what I wanted to do - I wanted a new challenge and soon as I heard there was a chance of stepping up I had to take it.

"I played quite a few games last season with Charlton and I just want to push on now. Like any young player, the first thing you want to do is get into the first team. I need to show the staff, players and the gaffer what I'm capable of doing and maybe pushing my way in.

"West Ham is a great Club with a lot of tradition, moving to a new stadium and everything, it was a no brainer for me because you never know if you're going to get that kind of chance again."

Poyet was born in Zaragoza, Spain, where his father Gus was playing for the city's Primera Division club, in April 1995.

At the age of two, he moved to London when Gus signed for Chelsea, and he has spent the vast majority of his life living in England.

An industrious and tenacious midfielder blessed with an impressive range of passing, Poyet signed for Charlton as an eleven-year-old before coming through the Academy ranks at The Valley.

The youngster's promise was recognised at international level as early as October 2010, when he was handed an England U16 debut in a Victory Shield meeting with Wales - a match which saw him captained by new West Ham team-mate Leo Chambers.

The following year, he lined up alongside Manchester United and England left-back Luke Shaw as the Young Lions won the Montaigu Tournament in France.

After being capped six times by England at U17 level, Poyet made his first-team breakthrough at Charlton in January 2014, appearing as a substitute in an FA Cup third-round victory over Oxford United.

The teenager made his full league debut a fortnight later at Wigan Athletic and became a mainstay in the Charlton side for the remainder of the campaign, contributing to the Addicks' successful battle against relegation with a series of Man of the Match performances.

Poyet becomes West Ham's fourth summer signing following the arrival of Argentine striker Mauro Zarate from Velez Sarsfield, Senegal midfielder Cheikhou Kouyate from RSC Anderlecht and left-back Aaron Cresswell from Ipswich Town.