Mr Serious has brought the case after Yahoo! registered its name as a trademark with the Australian Trade Marks Office. Serious objected to the application at the time, but the Trade Marks Office rejected his complaint. He is now appealing its decision.
The case will be heard in Australia's federal court next March.
The actor, who starred in films such as Young Einstein and Reckless Kelly, states on his website that he has been known as Yahoo by family, friends and professionally since 1980.
"My name is one of the artworks of which I'm most proud and obviously the one I feel closest to," he says.
If you have an opinion on this or any other issue raised on Brand Republic, join the debate in the .