Nicole Richie, green sweater, book signing

Nicole Richie and Joel Madden play coy about their wedding plans.

At a recent book signing event for "Priceless", Nicole and Joel chitchatted about their engagement and who won't be singing at their wedding.  The couple is rumored to be tying the knot in December, but they're working hard to keep it private.  Joel shared:  "Are we getting married? Of course we are, we're engaged. I don't know when it could happen with our schedules. I'm working this next year and a half."

Joel also shared that he'd love his father-in-law-to-be, Lionel Richie, to sing at their wedding.  However, Nicole put the kibosh on that plan: "I'm not down [with that]!" I'm guessing that maybe she just wants to her dad to enjoy the day and not have to "work" at her wedding?

Nicole recently enjoyed a bachelorette/birthday getaway with her girlfriends, which is why the rumor mill is buzzing with the expectation that they are getting close to the big day.  Whenever they do decide to get married, we wish them well!

Nicole Richie, Lionel Richie, suit, red carpet

Nicole Richie, book signing, green sweater, green turtleneck sweater