West Ham United are delighted to announce the signing of Spanish goalkeeper Adrian on a free transfer.

The 26-year-old will join the Hammers on 1 July after his contract with Primera Division side Real Betis Balompie expires. He has signed an initial three-year deal, with the Club having an option to extend this for a further two seasons.

An imposing 6'3 stopper, Seville-born Adrian - full name Adrian San Miguel del Castillo - has spent virtually his entire career with his hometown club, enjoying an outstanding 2012/13 season in the Spanish top flight.

After 16 years with his childhood club, Adrian is relishing the prospect of a new life and a new challenge in England.

"I am extremely happy and ecstatic to have joined such a legendary and historical club in both London and in England," he said. "I am really looking forward to being able to kick-off my career in the best league in the world with West Ham.

"I started off my career as a ten-year-old and have been there all of my life. I came through the ranks and I made my first-team debut in the sixth league game of last season against Malaga and was an ever-present since.

"For me, the icing on the cake was helping the team to qualify for the Europa League in, like West Ham, our first season back in the top flight after we had spent three years in the Second Division. Achieving this qualification was a massive farewell gift for the Betis fans."

After joining Betis at the age of ten, Adrian started his professional career with the club's C team in the Andalusia Premier Division. He then made more than 70 appearances for Betis B in the Segunda Division B Group 4, the regional third tier of Spanish football.

Adrian was also loaned to Segunda Division B clubs CD Alcala in 2008 and Andalusia Premier Division club CD Utrera in 2009 before being promoted to the Betis senior squad in 2011/12 as third-choice behind the experienced Casto and Fabri.

When Casto was sent-off at Malaga in September 2012, Adrian stepped off the bench and never looked back, starting each of Betis' next 31 league matches and producing a succession of impressive performances.

A tally of eleven clean sheets in 31 league starts helped Betis to finish the 2012/13 season in seventh place in the Primera Division table and to qualify for the UEFA Europa League.

Adrian's athleticism helped Betis to achieve a number of superb victories, including clean sheets in home wins over Real Madrid, Malaga, Valencia and Real Sociedad.

He is now targeting similar success with West Ham and is looking forward greatly to working with manager Sam Allardyce, goalkeeper coach Martyn Margetson and experienced stopper Jussi Jaaskelainen.

"I am very fortunate to be able to work with such an experienced goalkeeper with such a long track record in the Premier League as Jussi Jaaskelainen. I'm really looking forward to working with him on a daily basis and being able to receive tips from him which I'm certain will make me an even better goalkeeper.

"The same goes for the Gaffer. It's going to be an honour to be under the wing of such an experienced manager and that can only serve to make me a much better player.

"There is a very competitive squad at West Ham and, in my opinion, competition is what makes the group stronger and helps the Club to go further in the competition.

"West Ham had a great season after being promoted and, as a group, we should set our sights even higher because that is the only way we are going to improve our performances. We should be setting our sights on improving our league position this season.

"I am looking forward to joining the squad and becoming one of the group and trying to improve myself and the team's performance on the pitch."

He is also eager to prove himself to the West Ham supporters as soon as possible and, while his English is not yet fluent, he has already learnt one familiar Boleyn Ground chant.

"I am really looking forward to starting my relationship with the West Ham fans. From what I have seen, the fans are very similar to those at Betis because they are very passionate.

"If I can replicate the same relationship that I had with the Betis fans, I'll be a very happy person. Come on you Irons!"

Adrian becomes just the fourth Spaniard to join West Ham following strikers Kepa Blanco and Diego Tristan and fellow goalkeeper Manuel Almunia.