Charlton have signed striker Tony Watt for an undisclosed fee from Belgian side Standard Liege.
The former-Celtic striker has signed a three-and-a-half-deal with the Addicks after a disappointing spell outside of the UK.
Watt's greatest moment to date is scoring the winner in Celtic's 2-1 triumph over Barcelona at Celtic Park in 2012.
Despite being 21, Watt has experience at the highest level with Celtic and has represented his country at U21 level nine times.
Charlton head coach Bob Peeters told the club's website: "He's a guy who can score goals, he has a lot of pace, especially round the back of the defence, and although he's only 21 he has a lot of experience already and has played in the Champions League."
Watt moved to Celtic in 2011 from fellow Scottish club Airdrie United before moving abroad.
The Scot moved to Standard Liege following an spell on-loan with fellow Belgian league side Lierse SK.
Having made 17 appearances for Standard, Watt has decided to ply his trade a bit closer to home again in the Championship.
Watt becomes Charlton's third signing of the January window in just a matter of days.
Athletic have also signed goalkeeper Marko Dmitrovic and Neil Etheridge in an attempt to climb up the table towards the playoffs.