Image Credit: Tim Boyles/Getty Images

ABC News' Ben Forer and James Wang report:

It has been almost two months since Kevin Costner eulogized his friend and co-star in "The Bodyguard"  Whitney Houston, but only recently did he reveal that only after he was asked to speak at her funeral was he able to find the words to match his emotions.

"The way we work now, everyone needs to talk about it and people certainly wanted me to talk about it and I didn't really have the words at that point," Costner told ABC News' Diane Sawyer. "Dionne Warwick called me and said, 'would you speak?'And I could feel how broken she was and how tired she was, and I said that I would. I think the moment I said I would, I went 'Oh my God. What have I just done?' Because, that's such a specific moment and to so many people and I'm thinking … why am I speaking? Why am I there?"

In his speech, Costner remembered Houston as someone who shared the same interests and values. Both grew up in the Baptist church, a bond he said they shared over the years of their friendship.

Costner recalled Houston's nervousness when she had to do a screen test for the role of singer Rachel Marron in the movie.

"The Whitney I knew was still wondering if I'm good enough. Am I pretty enough? Will they like me?" he said. "It was what made her great, and what caused her to stumble at the end."

Costner told Sawyer that he was relieved when he finished speaking, but had one regret.

"I didn't even go over to Whitney's mom and everyone else went over and hugged her and I kind of went as quickly as I could to my wife and thought, man, I did that wrong," he said. "I should have just gone over to Whitney's mom. … I wish I could have done it differently. I wish I had gone over and given her a hug."

Costner is now lending his words to another meaningful ceremony on April 14, helping dedicate a memorial in honor of the soldiers from the 11th  Aviation Command in Fort Knox, Ky., who were killed in the war on terror.

For the last seven years Costner has performed with his country band, Modern West, and their song, "The Angels Came Down," struck a chord with military families who lost loved ones in the line of duty. Costner will be speaking at the event on Saturday where the song will be dedicated to all military families.

"While the song is about this last moment of a soldier's life, it's really a song for the living because if you've ever lost anybody or known anybody you're clearly haunted by that last moment of wondering if you're lost one was alone, if they were frightened, or you know if anyone was with my son," Costner said. "This loss of a child, a husband, a daughter - we know that a song can't heal that but … 'When the Angels Came Down,' that's what we like to think, that when our loved one was suffering the most that angels covered them, taken away their fear, and took away the pain. And if we can live with that idea, I think we can all sleep a little better."