Nicole Richie and Joel Madden have finally confirmed that they're engaged! "Yeah we've been engaged for a while so your all kind of late on that. But Thanks for the hooplah all the same," Madden tweeted yesterday. The couple has been dating for over three years and have two children together, 2-year-old Harlow and 5-month-old Sparrow. Richie did her part in confirming the news on Late Night with David Letterman, where she flashed her gorgeous, vintage-style Neil Lane diamond engagement ring.