Spanish international midfielder Gaizka Mendieta has joined Middlesbrough on a one-year loan from Lazio.
"We're absolutely delighted to have signed Gaizka," said Middlesbrough manager Steve McClaren. "We have worked extremely hard and beaten a lot of other clubs to bring to Middlesbrough a truly top quality player.
"His signing shows not only what an attraction we now are for top players but just how ambitious we are too".
The 29-year-old joined Lazio from Valencia for £28.9 million sterling just two years ago after twice reaching the Champions League final with the Spanish side in 2000 and 2001.
A Middlesbrough club spokesman said the initial deal could be extended for four years at the end of the season.
Mendieta played 20 Serie A games for Lazio before being loaned to Barcelona, for whom he scored four times in 33 league appearances last season.