"It seems we are very cool. Fox asked us for permission to use the video to promote their program, and we gave it to them," Arne Svare, head of Concorde, the company which produces the brothers' chat show Tonight with Ylvis , told Dagbladet.
In the new Fox advert, celebrities including Jane Lynch from the television series Glee sing along to the chorus of the Norwegian brothers' hit song.
Bard Ylvisåker, one of the two brothers, told VG that Fox's decision to use the song, which was originally intended simply to promote their chat show, was "absolutely insane".
The song is now the 5th most popular video on Youtube in the US, behind Miley Cyrus, Britney Spears, a video showing waiters' reactions to outrageous tips, and an advert for the Chipotle iPhone game. It is close to passing 35 million views.