Lazio midfielder Gaizka Mendieta has joined Middlesbrough on a year-long loan deal with a view to a four-year move.
Mendieta has lost his Spanish international place
Boro boss Steve McClaren secured the player's signature ahead of at least two other clubs, including Atletico Madrid and Athletic Bilbao.
Boro will unveil their latest capture at a news conference on Friday afternoon.
"We're absolutely delighted to have signed Gaizka," said 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.
"I came across Gaizka many times in European competition when I was with
Manchester United and he was at Valencia.
"He was undoubtedly one of the best players in Europe at that time. He was so good that Lazio paid nearly £30m for him.
"As Boro fans know, we've spent all summer searching for a quality player to
replace Geremi on the wide right. I'm confident we've got the ideal player in
"He is extremely skilful and we believe he'll bring much creativity to our
play, while also contributing towards our goalscoring."
The Spaniard has scored eight times in 40 appearances for his country, but has fallen on hard times since his move to Lazio.
He began his career at Spanish Second Division club Deportivo Castellon, before making a £28.9m switch to Lazio from Valencia where he reached the Champions League Final in 2000 and 2001.
But things did not work out at the Olympic Stadium and he spent much of last
season on loan back in Spain at Barcelona.
However, the Catalan giants decided not to make his move permanent and Boro beat off competition from Atletico Madrid and Athletic Bilbao.
Mendieta's agent Alberto Toldra said: "It was Mendieta's decision to choose Middlesbrough. He had four other offers to choose from."
Mendieta's capture will relieve the pressure on McClaren who has spent a frustrating summer attempting to bolster his midfield.
McClaren has seen summer targets Geremi, David Dunn, Trevor Sinclair, Brett
Emerton, Stephane Dalmat and Flavio Conceicao end up elsewhere.
To date, only Brazilian Doriva, who spent the last few months of last season
on loan at the Riverside Stadium, has been added to midfield, along with defender Alan Wright from Aston Villa.
McClaren is keen to add further strength and the Boro boss still has his sights set on Fulham midfielder Sean Davis.