The Greece international has completed his move to Craven Cottage, giving Rene Meulensteen's men a big boost as they battle to avoid relegation from the Premier League.
The Cottagers agreed to a deal for the Greece international in Thursday, Goal UK reported, after the striker completed a medical at the west London club’s Motspur Park headquarters.
The striker has now completed his transfer for a fee worth 11 million pounds.
Mitroglou has scored 23 goals in 25 matches for club and country this season, including a hat trick in the Champions League against Anderlecht.
The 25-year-old could prove to be a replacement for Dimitar Berbatov, who is set to join Monaco after travelling to France to complete his transfer to Claudio Ranieri's side.