O'Neill ties up £5m swoop.
Sunderland have completed the signing of striker Danny Graham from Swansea City.
The 27-year-old arrives on Wearside for a fee of £5m and has signed a three and a half year deal.
Graham, who is expected to be available for Saturday’s game at Reading, has scored more than 100 career goals and says he will give his all to make his mark on Wearside.
“As soon as I heard about the interest from Sunderland I didn't even have to consider any of the other options that were on the table,” he told safc.com.
“I was born and brought up in the north east so I know first-hand the intense passion that people have for their football in this part of the world – it's special and there's nowhere else like it.”
The striker, who was born in Gateshead, added: “Of course, I totally understand that some fans might need convincing about my commitment to Sunderland because of my roots, but I've always given 100% no matter what team I play for and no matter who I play against.
“It's up to me to show people I deserve to wear the Sunderland shirt and I'm excited about playing for a club as big as this.
“I'm really excited about the future – this is a new phase of my career and I can't wait to get started.”
Graham is Martin O'Neill's third signing of the January transfer window following the arrivals of midfielder Alfred N'Diaye and defender Kader Mangane.
The former Middlesbrough, Carlisle and Watford frontman was Swansea's top scorer with 14 goals last season and has netted a further seven times this term.
Graham will wear the number nine shirt for Sunderland.