Naomi Campbell (search) says she nearly self-destructed from her use of cocaine.

Campbell tells Diane Sawyer (search) on "Primetime Live" (to air at 10 p.m. EST Thursday) that she's glad she recovered, but acknowledges that it's still difficult.

"It was a rebellion in a certain way. You know?" the British supermodel says. "I don't want to be in that pain again. I don't want to be in that place."

Campbell, 34, said she first tried cocaine when she was 24 but stopped before "something would have happened. Some self-destructive thing."

"I never did drugs before I would go on the runway because I knew that's when I was an active addict. I knew that they could see my eyes," she said.

Campbell said she assumes others knew of her addiction at the time. "People aren't stupid. ... you think people don't know, but they know. They know. I mean, that's your mind playing tricks on you."

In 2004, she won her appeal in a privacy case against a London newspaper that published photographs of her leaving a drug counseling meeting. Her lawyer said Campbell hadn't objected to the Daily Mirror's reporting that she had a drug problem and had misled the media about it, but only to its publication of details of her treatment.

In the "Primetime Live" interview, Campbell also discusses some of the more glamorous aspects of her life, including a reported romance with R&B singer Usher (search) — though she says the two were never a couple.

"We're still friends," Campbell says. "We were never boyfriend/girlfriend. ... One of the reasons why I felt like I needed to pull back is because it was getting misconstrued."