Credit: Michael Rozman/Warner Bros.

Nicole Richie says she'll be walking down the aisle in the very near future.

Asked on Tuesday's Ellen DeGeneres Show if she and Joel Madden have set a date, Richie, 28, says they'll be marrying "soon."

"It's a big deal," she says of the wedding preparations.

She says she isn't sure how big the ceremony will be.

"I've been on the road," says Richie, who just returned from Europe where she presented her fashion collection line Winter Kate and House of Harlow 1960. "I just got home, so it's really going to be like now that's the time for me to sit down and think about what I want."

On E!'s pre-Oscar show Monday, Richie joked that she and Madden, 30 -- who began dating in December 2006 -- would be wedding "tomorrow."

Kidding aside, Madden said of their wedding plans: "The same thing as our engagement, we're kind of doing it at our own pace. We have no idea right now."

They have two children, Harlow, 2, and son Sparrow, 5 months.