Remembering Steve Irwin With Last Film

Four months ago, Steve Irwin was filming the documentary "Ocean's Deadliest" for Animal Planet when he was fatally wounded by a stingray.

The filmmakers have just completed the documentary, which shows the wildlife expert at his best: strong, vibrant and doing what he did best.

The chief ocean correspondent for Animal Planet, Philippe Cousteau, narrated the film and was there when Irwin died. It was the first time he had ever worked with the crocodile hunter.

"I was amazed by what a great, considerate and sincere guy he was with his work and on and off the camera," Cousteau told The Early Show co-anchor Harry Smith. "How much fun he was, what a jokester he was, and how much fun we were having."

Cousteau said there were moments during filming that he sometimes felt cautious and concerned about working with dangerous animals, but he never expected Irwin's life to come to a tragic end.

"It's something that will stay with us for a long time," said Cousteau, who tried to revive Irwin. "It was definitely one of the worst days of my life. It went being from one of the best weeks — we were having such a great time — to, in a heart beat, a terrible tragedy."

After Irwin died, Cousteau and the film's producers decided that they had no choice but to finish the piece as a tribute to Irwin. Even though Cousteau only worked with him for two short weeks, he said he would be inspired by Irwin's passion and commitment forever.

Cousteau said he and Irwin gelled right away, especially over their passion for wildlife. The documentary prompted Cousteau to try things he had never done before, like swim with a great white shark.

"It was incredible. These animals that have such a bad reputation are much more thoughtful and graceful, with such purpose," he said. "That's the theme, all these animals that are deadly and dangerous, they have an important role to play and the deadly creature is really man."

"Ocean's Deadliest" airs on Animal Planet and Discovery on Jan. 21.