Nicole Richie is insisting she is a changed person for the sake of her unborn child, due in five months.
"I would really want to be someone my child would look up to," Richie, 25, told ABC's Diane Sawyer in an interview that aired on Thursday's Good Morning America. (Part two will air Friday and address Richie's being "scary skinny," said Sawyer.)
Richie also admitted that her upcoming four-day jail sentence for her DUI arrest on Dec. 11 leaves her "afraid of the unknown," but added, "This is my way ... of being an adult."
After being described by Sawyer as "rich, reckless, in trouble" and into "drugs, rebellion [and being] frighteningly thin," Richie, with her Good Charlotte rocker boyfriend Joel Madden sitting at her side, said her behavior transformation came after seeing images on TV of children who had been killed by drivers under the influence.
"That was our first real parent moment," interjected Madden, 28. Both he and Richie said those images forced her last Friday to change the plea in her case to guilty.
Madden also admitted that when Richie was arrested, he saw it as a possible breaking point in their relationship.
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Explaining what she had been doing just before her arrest – when police stopped her 2005 black Mercedes SUV as it was going the wrong way on a freeway off-ramp – Richie said, "I had smoked marijuana that day."
"Just marijuana?" asked Sawyer.
"Just marijuana," said Richie. "I had Vicodin in my system from that day. I never in my head thought that could play a part in your driving. Like, never did I think that. It was hours ago." Richie said she took the powerful pain killer for her severe menstrual cramps.
"I literally thought I was okay to drive, and clearly wasn't. It was bad decision after bad decision after bad decision," she said. "It's been a pattern in my life. When I get into trouble, I try to get out of it."
Describing her pattern of the past year, she said, "I wasn't growing, I wasn't going anywhere, and I saw myself going down that road again with this particular situation."
Pressed by Sawyer about drug use, Richie responded, "I don't take anything now."
On a lighter note, Richie appeared bubbly when talking about her baby, whose sex she does not yet know. As for being pregnant, "I didn't really believe it until I heard the heartbeat."
Her father, musician Lionel Richie, didn't believe it at first either, the couple revealed. When they called to tell him, said Madden, the elder Richie thought it was more news that his daughter was in trouble.
But then, Lionel Richie went silent, according to the couple, After a moment, however, he loudly told Nicole, "Now you're going to get to experience everything I have!"