Pamela Warner, the mother of late actor Malcolm-Jamal Warner, is opening up for the first time about her son's drowning death earlier this summer.

Malcolm-Jamal, best known for playing Theo Huxtable on The Cosby Show, died on July 21 at age 54 while in Costa Rica. During a recent interview with Good Morning America's Robin Roberts, Pamela said her son went to Costa Rica to join his wife, Tenisha, and their eight-year-old for the final week of an immersive homeschooling program abroad.

“His wife and daughter had been in Costa Rica three weeks prior,” Pamela explained. “She is homeschooled, and this was part of an immersion program.” She said the final week was meant to be “the fun part,” adding, “It was for the husbands to come.”

Pamela also addressed reports surrounding her son’s death, clarifying that his daughter was not in the water at the time of the drowning

“She was not in the water. He was with another gentleman,” she said. “They were in the water, I think maybe chest deep — maybe even waist deep. There was an undertow, and my son was not an experienced swimmer. He did not know how to deal with an undertow.”

“The same [undertow] happened to the other gentleman, but he was a more experienced swimmer and he was able to rescue himself. But Malcolm was not," the actor's mother added.

Pamela told Roberts she felt an "indescribable pain" when she learned of her son's death.

“It was from the bottom of my soul. And what came up and what came out was huge — it was an indescribable pain that resonated throughout my body.”

According to Pamela, Warner’s eight-year-old daughter is struggling to process her father's death.

“She watched them try to resuscitate him, so she saw that,” Pamela said. “And I know that’s awfully, awfully traumatic. She loved her father dearly. She adored Papa — he was Papa.”

Both Tenisha and their daughter are “in deep grief,” Pamela added.

Tenisha Warner recently spoke out for the first time since her husband's death and launched the Warner Family Foundation and River & Ember, an initiative she and her daughter created to support emotional wellness and artistic expression in children.

“Tomorrow marks our anniversary — and my heart is wide open,” Tenisha wrote in a Sept. 12 Instagram post, sharing a photo from their 2017 wedding. “I can still hear my husband’s laugh, still feel the way he made room for every part of me — every tear, every dream. Together we carry the legacy my husband and I began — one that nurtures children’s inner light and gives young artists the freedom to create outside the lines.”