Ryan O'Neal gives his first interview since the death of his longtime love Farrah Fawcett -- and ET has a sneak peek.

On Tuesday, July 21, Meredith Vieira sits down with O'Neal on NBC's "Today" show to express her condolences and to find out how he is coping.

"Well, I'm the new rock. And -- I'm using what she taught me to -- to survive. To go on," O'Neal tells Vieira. "To care for my son, Redmond. And -- and -- I have launched into this massive job of answering the mail that has come in for her over the last few weeks. Hundreds and hundreds of letters of -- of -- pain and sorrow and hope and -- so I -- I'm answering them. Every one. That's my life now. It's gonna take a while."

Here is more of the interview:

Meredith Vieira: Yeah. I can hear in your voice, Ryan, that you're hurting very much.

Ryan O'Neal: She was big. She was big.

* * *

Meredith Vieira: He's [Redmond] in a facility for drug possession. And one of the most touching moments, in the documentary-- of "Farrah's Story" is when he was released to go visit his mom before she entered the hospital. And he went to her home in shackles. It was extremely moving. And when she passed away, he could not be there for her. But he did call her, you said, to tell her how much he loved her and how sorry he was.

Ryan O'Neal: He spoke to her a number of times. He spoke to her a number of times on the cell phone. And, also, he was at the funeral. He came and-- and-- and they allowed him to carry her casket with-- with the other pallbearers. Although, they didn't take his handcuffs off. So he just kept them under his sleeves and-- and he's-- he-- he buried his mother. He got to bury his mother. And then the sheriffs took him back.

Meredith Vieira: In those last calls to-- to his mom, what did he say to her?

Ryan O'Neal: Well, I held the phone to her ear. So I'm not exactly sure. But I think it was about regret. And the horror of -- of not being able to see her again. And the promise -- the promise of a good life. Of a life that she would be proud of. And -- because he is her legacy. And he now knows that, finally, it's clear. And he has a plan. A wonderful plan in mind to restore order in his life. And he will, with my help.

Meredith Vieira: You know, we talked to Dr. Lawrence Piro (PH) right after Farrah passed. He had been in the hospital with her, along with you and her best friend, Alana Stewart, and he said, up until the end, almost to the end, she was alert and awake. Can you describe the atmosphere in her hospital room?

Ryan O'Neal: It was horrible. It was horrible. It was -- he thought that she would live just another couple of hours, and she lived a couple of days. So I had a bed put in the room for me. And I just lay by her side. And she wouldn't -- move on. She wouldn't pass. She just -- she just looked at us with-- with a slight smile. Was awful. And then -- and then all the machines flat lined. After about -- 16 hours. And she was -- she was gone.

Meredith Vieira: What were the last words, if you would share with us, and I --and -- and please, if you don't want to, I understand, but the last words that she said to you, and the last words that you said to her, Ryan?

Ryan O'Neal: I said I'd see her soon. And I see her every day. And I write to her. I write in my journal now, to her. And -- and Redmond says he -- he's trying to see her. It's a little harder in a reformatory. To grieve. So I told him to be patient. And, when he got out, we'd grieve together. We'd -- but we all kissed her goodbye and hugged her and held her. And didn't want to let her go. It was something that I had never experienced, and I'd done a movie about it, but I'd never experienced it.

For more of Vieira's interview with Ryan O'Neal, watch Tuesday's "Today."