Actor Terence Knox fights a constant battle on two different fronts.

As the star of Tour of Duty, Network Ten's new Vietnam War series, he faces grueling physical demands every day.

Tour of Duty is filmed in Hawaii, a tropical paradise if you're a beach-loving tourist, but it can be hell if you spend your days in jungle greens, carrying around full combat pack and a heavy weapon.

On the other front, the enemy is none other than Bill Cosby. America's CBS has decided to try to break Cosby's ratings stranglehold with Tour of Duty and so far the war series has rated a respectable second.

"The Cosby thing will take care of itself," Terence says as he grabs a hasty lunch on a windswept hillside near Koko Beach, Honolulu.

"Either we'll get better or we'll be moved. The network, in its wisdom, says it likes what it's getting.We're an important show and they know it.

"The elements out here doing this are the worst part.Let's just say the Hawaii is not what it's cracked up to be if you're not on the beach at Waikiki all the time.

"I haven't seen a bikiki in three months. Sometimes it rains like hell out here and we look through the clouds and see the beaches and we know that some tourist is getting a tan.

"Believe it or not, I miss the Santa Monica Freeway in Los Angeles. I've been here since last August and I've been home only three times.

"All I have at home is my two cats and my loft and my little Austin Healy, but I miss all that."

With a broad grin, Terence adds that if Tour of Duty becomes popular in Australia it could change his life dramatically.

The cast of the show uses the same Honolulu hotel through which a fetching parade of Qantas stewardesses regularly passes.

"Once this hits the air in Australia it could mean a hell of a lot!" quips the good-looking star.

Terence, probably best known to Australian audiences as Dr Peter White in the medical drama St Elsewhere, plays war-weary platoon sergeant Zeke Anderson in Tour of Duty.

"He's sort of like me at the moment. I'm at my best here at work and my social life is a mess.

"A girl I was seeing made no bones about it—she liked my character more than she liked me!"

Terence acknowledges that cinema successes such as Platoon and Hamburger Hill have encouraged television to touch on the Vietnam War—the "unpopular" war.

"Platoon especially probably gave an indirect mission to the network to go ahead with this." he says

"But by now, having done a lot of episodes, I think in terms of quality and the knowledge that we have about what we're doing that we're so far beyond Platoon it's hard to give the movie credit.

"But I am able to because I remember that before Platoon there was no TV show and now there is."