Middlesbrough sign up goalkeeper Valdes

The 34-year-old -- who won European club football's most prestigious trophy with Barcelona -- had a miserable time at Manchester United under then-manager Louis van Gaal, playing just twice before falling out with the Dutchman and being loaned out to Standard Liege in Belgium.

However, his compatriot, Middlesbrough manager Aitor Karanka, is ecstatic to have secured the former Spanish international's signature.

"You can't imagine how delighted I am because it's not usual to bring players like him to recently promoted teams," Karanka told mfc.co.uk.

"I'm really pleased because he is really committed. All the conversations we've had he knows why he is here and he is coming to add to what we have," added Karanka, who is a former assistant coach of Barcelona's bitter rivals Real Madrid.

Valdes, who also won six La Liga crowns in his 13 years with Barcelona, as well as winners medals at the 2010 World Cup and Euro 2012, is Karanka's fifth capture since Middlesbrough gained promotion.

Dutch defensive midfielder Marten de Roon, Scottish teenager and Under-21 international defender Jordan McGhee, Viktor Fischer and Colombian defender Bernardo Espinosa are the other new faces as 'Boro prepare for the Premier League campaign that gets under way in August.

De Roon signed earlier this week from Italian side Atalanta, Espinosa joined from Spanish side Sporting Gijon whilst Danish winger Fischer came from Dutch giants Ajax for £3.8 million ($5.3 million, 4.8 million euros).

The 19-year-old McGhee signed on a season-long loan from Hearts.