Newcastle have confirmed that Chelsea full-back Celestine Babayaro will become Graeme Souness' first transfer window signing on New Year's Day.
The 26-year-old, who would have been out of contract at the end of the season, moves for an undisclosed fee.
Babayaro looks set to make his debut in the FA Cup third round against Yeading.
The left-back can also play in the Uefa Cup for the Magpies as he has not featured in Chelsea's Champions League campaign despite being on the bench.
A Newcastle spokesman confirmed: "The player will be transferred for an undisclosed fee on 1 January.
"He also qualifies to appear in the FA Cup and Uefa Cup, the latter being because although nominated as a substitute, he has not taken the field for Chelsea in European competition this season."
Babayaro won the FA Cup, League Cup, Charity Shield and European Super Cup during his seven-and-a-half years at Stamford Bridge, but has been out-of-favour since Roman Abramovich's millions allowed Chelsea to embark on a spending spree.
The Nigerian's arrival at St James' Park leaves a question mark over the future of Olivier Bernard who is yet to agree a new deal and will be out of contract at the end of the season.
Souness is also looking at bringing in other defenders to shore up hjs leaky defence, but has ruled out increasing his £8m bid to lure Jean-Alain Boumsong from Rangers.