After months of rumors, Nicole Richie confirmed Tuesday that she is pregnant.

"Yes I am. We are," Richie told ABC News' Diane Sawyer in an interview to be aired this week. "I'm almost four months."

Richie's boyfriend, Good Charlotte frontman Joel Madden, is the father.

The 25-year-old star of "The Simple Life" and on-again Paris Hilton pal also talked with Sawyer about her guilty plea last week for driving under the influence and resulting four-day jail sentence.

"I have a responsibility and it's something that I did wrong, and if I could personally apologize to every single person that has lost a loved one from drunk driving, I would," Richie said. "And unfortunately I can't, but this is my way of paying my dues and taking responsibility and being an adult."

Richie also shared her thoughts on her hard-partying contemporaries and what effect their bad behavior has on young fans.