Howard was among those in attendance in the 5,500-seat capacity "Crocoseum" at Queensland's Australia Zoo for the one-hour ceremony. Irwin, 44, died Sept. 4 from the barb of a stingray while he was filming on the Great Barrier Reef.
Also paying tribute were Russell Crowe, Justin Timberlake, Cameron Diaz, Hugh Jackman, Kevin Costner, Kelly Ripa and Larry King and Australian country singer John Williamson, who sang one of Irwin's favorite songs, "True Blue."
But it was the composed 8-year-old Bindi Irwin who best represented the spirit of the event. With her mother Terri holding Bindi's toddler brother Bob, Bindi read her words to the crowd, running her tiny finger across the paper as she went along.
"I don't want Daddy's passion to ever end. I want to help endangered wildlife just like he did. I have the best daddy in the whole world, and I will miss him every day. When I see a crocodile I will always think of him, and I know that Daddy made this zoo so everyone could come and learn to love all the animals. Daddy made this place his whole life, and now it's our turn to help Daddy."
When Bindi finished, she wrapped her right arm around her mother's neck as a visibly upset Terri held tightly onto Bob. Bindi finished by taking center stage and feeding elephants that were parading around the croc pool.
Crowe, in a videotaped message from New York, said, "We've all lost a friend. We've all lost a champion, and we're going to take some time to adjust to that." Addressing the late Irwin, he said, "As humble as you always were, you will still be pleased to know that the world sends its love and that people all over this planet have been grieving."
Diaz, also in a video presentation, said that America was "just taken by him ? in awe of his energy and how he actually went about putting himself forward. Every kid was in love with the idea of being able to be him."
In a separate video, Timberlake (who had visited the Australia Zoo with Diaz in 2004) said, "To Terri and Bindi and Bob and Steve's family and friends, I may have only really spent a day with you guys, but it was a day I'll never forget, and I'll never forget what I learned just by being around Steve."
Added Steve's father, Bob Irwin, 66, "Please do not grieve for Steve, he's at peace now. Grieve for the animals. They have lost the best friend they ever had, and so have I."
After the service, Bob Irwin told reporters, "I was coping fairly well until John sang that song, and then I fell apart. Steve really loved that song. He was a true blue Aussie and a really good bloke."
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