The 24-year-old Scotland international has signed for an undisclosed fee, understood to be in the region of £2.5million.
Bridcutt, who will wear the number 23 shirt, had not played for the south-coast club since submitting a transfer request earlier this month after the Black Cats formalised their interest in him.
The club confirmed that capture via Twitter:
Poyet has already signed Marcos Alonso on loan from Fiorentina and Argentinian pair Oscar Ustari and Santiago Vergini this month, while compatriot Ignacio Scocco was in the crowd for Wednesday night's 1-0 Barclays Premier League win over Stoke which lifted Sunderland out of the bottom three for the first time since August.
Bridcutt's arrival could yet have implications for Lee Cattermole, who has been linked with a move to Stoke this month, although Potters boss Mark Hughes insisted after the game against Sunderland on Wednesday that no offer had been made.
- Sports & Recreation
- Barclays Premier League
- Oscar Ustari
- Santiago Vergini