Adele raised her middle finger when host James Cordon unexpectedly cut in her speech, to introduce the next musical performance.
However, Adele said the middle finger was not for Cordon, but for the producers of the show.
"I flung the middle finger. That was for the suits at the Brit Awards, not my fans. I'm sorry if I offended anyone but the suits offended me," the 23-year-old singer told the BBC of the instance that was live broadcast.
During her speech, the British singer expressed her gratitude about her success. "Nothing makes me prouder than coming home with six Grammys and then coming to the Brits and winning album of the year. I'm so proud to be British and to be flying our flag."
After Cordon, who was hugely met with boos from the crowd, stepped in, Adele asked "Can I just say, then, goodbye and I'll see you next time round?" followed by her flipping off the cameras.
Adele also bagged 6 awards from all her nominations in the recently-held Grammy Awards.
Watch the video below and the complete list of winners of the 2012 Brit Awards right after.
2012 Brit Awards winners
Best Male Solo Artist: Ed Sheeran
Best Female Solo Artist: Adele
British Breakthrough Act: Ed Sheeran
British Group: Coldplay
British Single: One Direction - What Makes You Beautiful
British Album of the Year: Adele - 21
International Male Solo Artist: Bruno Mars
International Female Solo Artist: Rihanna
International Group: Foo Fighters
International Breakthrough Act: Lana Del Ray
Critics' Choice: Emeli Sande
British Producer: Ethan Johns
Outstanding Contribution to Music: Blur