Vegard and Bård Ylvisåker hope to milk millions from selling official t-shirts, hats, perfume, jewelery, and even films linked to their YouTube hit, The Fox, which on Tuesday passed 100m views.
"We want to protect our own name and exploit it commercially. We want to take control," Jørgen Thue, who runs the brothers production company Concorde, told VG. "We are thinking of course of reaching out to the world. Anything else would be silly when we have a worldwide hit."
The two brothers yesterday flew to the US, where they are scheduled to appear on Late Night with Jimmy Fallon.
"I am so glad I do not have to deal with all this," Bård Ylvisåker said of the trade mark application. "It's very strange but nice that people are making T-shirts and knitting hats themselves."