The Aston Villa midfielder has joined the club on loan until the end of the season.
The Villa talent has been linked with a move to Forest all week and now the deal is done he will hope to once again impress in Forest colours.
However, it would seem that Forest had to beat off some strong competition for his signature - from Championship rivals Leeds United.
Forest boss Dougie Freedman told BBC Nottingham Sport this afternoon that Gardner knocked back Leeds' interest in order to join Forest again:
"I want to sign players that want to come here. Not that they want to come here because their agent told them too or their pay or whatever happens.
"I want players that want to play here and Gary expressed a real strong interest. I think he said no to a few other clubs, I think Leeds were interested in him a couple of days ago, and he's knocked them back to come to a place where he knows where he's loved and he's wanted and he brings that certain desire."
Leeds are actively pursuing many leads in the transfer market and Gardner could have added depth to the central midfield area - despite the club already re-signing Liam Bridcutt this window.
But Forest were always likely to win this battle.
Gardner was at the City Ground last season and scored four times in 18 appearances for the club.
Forest fans will be hoping that he can have a similar impact at the club this time around.