LOS ANGELES (Zap2It.com) - This weekend, Australian actor Heath Ledger will join Mel Gibson in ``The Patriot,'' an historical epic which many expect to be a blockbuster. Many also expect Ledger, who plays Gibson's son, to become a hot commodity on the basis of this film.

But this isn't the first time that American audiences have seen Ledger.

He was in the American film ``10 Things I Hate About You,'' but he also played an Irish warrior in the 1997 FOX series ``Roar,'' created by Shaun Cassidy (``American Gothic,'' ``Cover Me: Based on the True Life of an FBI Family'').

Pulled after only a few airings, ``Roar'' still has several episodes that have never aired in the U.S. ``There are a few of those,'' says Cassidy. ``Nothing stays in the vault forever. And Heath Ledger's about to become a big movie star, I'm sure. He's on his way.''

FOX, though, had one more chance to snag Ledger, during the initial development phase for ``Roswell,'' currently renewed for a second season on the WB. The drama about teen aliens was originally developed for FOX under the title ``Roswell High'' (the same as the series of young-adult novels it was inspired by). It currently stars Jason Behr, Katherine Heigl and Brendan Fehr as three humanoid aliens; and Shiri Appleby, Colin Hanks and Majandra Delfino as the human teens that love them.

''Roswell'' executive producer Jonathan Frakes tells Zap2it.com, ``FOX had Heath Ledger. We could have had Heath Ledger. We tested Heath Ledger for Jason Behr's part. FOX refused to take him because of `Roar.' Because `Roar' bombed, they tested him and didn't hire him.''

Any regrets? ``Oh, man,'' says Frakes, ``but I think we did pretty well with Mr. Behr.''