Scott Hogan has thanked Brentford supporters and the club for "sticking by him" during his protracted move away from the club.
Hogan, 24, joined fellow Championship side Aston Villa on Tuesday for a fee that could rise to £12m.
In a statement posted on Twitter by former team-mate Harlee Dean, Hogan apologised for how the move unfolded.
"Thanks for everything, it's been a couple of years which I will never forget," Hogan said.
Hogan was the centre of speculation for much of the January transfer window, with West Ham the initial favourites to secure his signature.