Sunderland have completed the signing of Norwich City midfielder Dickson Etuhu for £1.5m.
Etuhu started 42 league games for the Canaries last season
The 25-year-old former Manchester City and Preston player turned down an improved contract offer from the Canaries at the weekend.
And the Nigerian becomes Roy Keane's fifth summer addition.
"We received an offer from Sunderland for Dickson which meets a £1.5m buy-out clause in his contract," said Norwich chief executive Neil Doncaster.
"We are very disappointed to lose Dickson, obviously.
"But the simple facts are that Dickson turned down the offer of a new, more lucrative contract from Norwich City which was already on the table, in favour of Sunderland's offer.
"We are therefore forced to accept their offer under the terms of his contract."
Sunderland boss Keane said: "He's a player I admire. He would give us something different to what we have got."
Etuhu began his career at Manchester City but started just 11 league games before signing for Preston in 2002 for £300,000.
He played nearly 150 games for North End before joining Norwich after a loan spell at Carrow Road.
Etuhu started 42 league games for Norwich last season - his first full campaign for the club following his £450,000 arrival from Preston in January 2006.
Keane completed the signing of Kieran Richardson from Manchester United on Monday for a fee believed to be £5.5m.
The Black Cats boss has also drafted in Greg Halford, Russell Anderson and Michael Chopra.
The deal for Etuhu brings the total of his summer spending to £15.5m as the club prepare for their return to the Premiership.