"She was having difficulty stopping," Crawford alleges of Whitney's drug use.
The singer's longtime confidant recently said, for the first time publicly, that the pair were lovers in her new memoir "A Song For You: My Life With Whitney Houston." In the book, she also addresses Houston's issues with drug dependency.
In an appearance on "Dateline," which was teased this morning on "TODAY," Crawford was asked by Craig Melvin when she first believed Houston had a problem.
"I would remind Whitney that, you know, we said doing coke couldn't go where we're going and we're already there. So we shouldn't be doing it," said Crawford. "I'd notice that she would go ahead and do it. She was having difficulty stopping."
Melvin then brought up claims from the book that, despite public perception, Houston's drug use began before she took up with Bobby Brown.
"That's true. She wasn't doing it [drugs] regularly, but she would do it sometimes and might, you know -- overdo it," claimed Robyn. "But, you know, Bobby, he didn't introduce her to cocaine, no."
Regarding Houston's tumultuous marriage to Brown, Crawford said another man in Whitney's life tried to talk her out of it.
"She was more interested in Eddie Murphy, but he was elusive.," she wrote in the book (via People), saying Houston "lost herself" trying to pursue the comedian. The day of her wedding to Brown, Crawford claimed "Eddie Murphy called to say she was making a mistake ... but she pressed ahead."
In another interview excerpt that aired earlier this week, Crawford opened up more about their alleged relationship.
"Our friendship was a deep friendship. In the early part of that friendship it was physical," Robyn said, adding, "We were intimate on many levels, and all I can say is that it was very deep and we were very connected."
"I would say no one," when asked who knew of their physical relationship, "It was ours."
But the physical aspect stopped because "the music business was a world we were learning and we didn't want anything to interfere with where she was going," explained Robyn.
When asked why she wanted to share her story now, Robyn offered, "I never envisioned speaking publicly about my life and then I asked myself the question what would Whitney want. Would she understand the time is now."
Robyn Crawford's memoir "A Song For You: My Life With Whitney Houston" is expected on shelves November 12.
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