Aston Villa beat the closure of the transfer window by a matter of minutes to sign Celtic forward Shaun Maloney for a fee of about £1m.
Maloney was last season's player of the year in Scotland
Maloney was at St James' Park to watch Villa lose 3-1 to Newcastle, having passed a medical, before concluding his transfer to the Premiership club.
And former Celtic manager Martin O'Neill told BBC Sport: "He has done very very well since I left Celtic.
"Shaun is one of the most conscientious young men I have known in the game."
Maloney was out of contract with Celtic at the end of the season and was involved in protracted negotiations to extend his stay with the Scottish champions.
But the 23-year-old Scotland international instead signed a pre-contract agreement to join Villa in the summer.
And O'Neill was keen to take him south during January.
The forward was player and young player of the year in the Scottish Premier League last season.
However, O'Neill was sure Maloney would be a big hit in English football.
"What he lacks in height, he makes up in a lot of ability and a lot of courage," he said.
"He is a smashing lad. But I am not signing him because he is a smashing lad. He is a quality player."