Will Grigg has joined Sunderland from Wigan in a £4m deal – a record for a League One transfer.
The striker has signed a three-and-a-half year deal at the Stadium of Light after the clubs agreed a fee and Sunderland lodged a deal sheet for the player before the 11pm deadline, with the transfer ratified by the EFL and the FA.
Sunderland made a breakthrough in their pursuit of the Northern Ireland international with their sixth bid for Grigg, whose signing overtakes John Brayford's £2m move to Sheffield United in 2015.
Grigg joins Sunderland as they target promotion to the Championship under Jack Ross, with the club sitting fifth in League One and four points off an automatic promotion spot although they have at least two games in hand on the teams above them.
The 27-year-old scored 65 goals in 150 appearances during his three-and-a-half year stay at Wigan and scored memorable winning goals, including the club's FA Cup victory against Manchester City last year and the title-winning strike at Doncaster Rovers in May.
"The club desperately wanted to keep Will but this is an offer we simply couldn't refuse," Wigan manager Paul Cook said.
"This comes with so much emotional attachment because Will is so popular with our supporters and is somebody who has given everyone associated with the club so many great moments during, not just my time as the club's manager, but throughout his three-and-a-half years at Wigan Athletic.
"We all wish Will the very best for the future."