Stephen Colbert says he turned to comedy to make his mother happy after plane crash killed his father and brothers

Stephen Colbert turned very serious on Tuesday's "Howard Stern Show" when he began to discuss the place crash that killed his father and brother and left his mother broken.

The late-night host was only 10 years old when his father, James, and his two older brothers, Peter, 18, and Paul, 15, were killed in the Eastern Airlines Flight 212 crash on September 11, 1974. It crushed him and his entire family.

"It's built into me the way like, the marble is built into the shape of a statue," He told Stern. "It's kind of, at a certain age, what I was made of."

The loss was especially hurtful to his mother, Lorna, so Stephen, the youngest of her 11 children, would tell her jokes to cheer her up. In fact, he said that's what formed his comedy career.

"I think there's no doubt that I do what I do because I wanted to make her happy. No doubt," Colbert revealed.

CBS's next "Late Show" host also spoke of the plane tragedy in an interview with GQ magazine released this week. He explained how his feelings have evolved to the point where he could still hate that the crash ever happened, but also be grateful that it did because it brought him to comedy.

The realization came to him on the street when he was 35 years old and contemplating something "Lord of the Rings" writer J.R.R. Tolkien wrote: "What punishments of God are not gifts?"

"[It] stopped me dead. I went, 'Oh, I'm grateful. Oh, I feel terrible.' I felt so guilty to be grateful. But I knew it was true," he remembered.

"It's not the same thing as wanting it to have happened," he said. "But you can't change everything about the world. You certainly can't change things that have already happened."

Colbert spoke with Oprah Winfrey about the accident on "Oprah's Next Chapter" back in 2012: