Cameraman Patrick McDermott, 48, hasn't been seen since taking a fishing trip June 30 off Southern California.
Lara Spencer, New York anchor for "The Insider," says this "really is a mystery. Was it an accident? Suicide? Murder? Nobody seems to know."
Last year on the Australian version of the TV show, "This Is Your Life," McDermott told the world how he feels about Newton-John.
And "The Insider" has an exclusive look at that show.
With Newton-John looking on from the show's stage, a video hookup shows McDermott saying, "I love you. ... The whole world loves you. Just let me start off by saying you look absolutely stunning and beautiful ... and I think everybody would agree.
"I'm sorry I can't be there in person to share this wonderful evening with you."
McDermott, who met Newton-John on the set of a TV commercial, is said to have been living with her in her Malibu home.
On "This Is Your Life," he continued, "Let me just say, I've known you for eight wonderful years, and you are such a special person, and you can be so compassionate, forgiving, understanding and gentle. You are the epitome of the word 'woman.'
"I love you with all my heart. … Enjoy this evening, and I'll talk to you later. I love you."
McDermott ended his tribute by throwing Newton-John a kiss. She smiled shyly and warmly as the audience cheered.