Whitney Houston’s struggles with addiction prior to her 2012 death were widely reported, and in a 2002 interview, she admitted she had a drug habit.

But Nick Gordon, former boyfriend of Houston’s daughter, Bobbi Kristina, tells Dr. Phil in an exclusive interview airing Thursday that he never saw Houston doing drugs.

“If Whitney ever did drugs, she was very private about that. I’ve never seen her do drugs,” says Gordon, who moved in with Houston and her daughter, Bobbi Kristina Brown, in 2011.

WATCH: Nick Gordon Opens Up About Bobbi Kristina’s Downward Spiral After Her Mother’s Death

“Did Krissy know? Did she ever confide in you that she knew?” Dr. Phil asks Gordon.

“No, she would have questions, but I don’t think so,” Gordon says.

Dr. Phil asks Gordon about reports that Houston and Bobbi Kristina did drugs together.

“That is so false,” Gordon says.

WATCH: Nick Gordon Discusses Bobbi Kristina Brown's Drug Use

“So you know that to be not true?” Dr. Phil asks.

“I can’t speak on before I was in the house, but to my knowledge, no,” Gordon says. “Whitney wouldn’t even stand for that.”

“If she had done it with her daughter, would you cover for Whitney now?” Dr. Phil asks. “If you did know it, would you tell me the truth?”

“Yeah,” Gordon says. “But that didn’t happen.”

Houston passed away on February 11, 2012 after being found face down in a bathtub. Bobbi Kristina died on July 26, 2015 at the age of 22, six months after being found clinging to life in her bathtub.

On Thursday’s episode of Dr. Phil, Gordon tells his story about the night Whitney died. And on Friday, Gordon addresses accusations that he murdered Bobbi Kristina.