Nicole Richie & Joel Madden: Engaged!

Nicole Richie and her boyfriend of over three years, Joel Madden, are making it official and planning to marry!

The 28-year-old fashionista revealed on The Late Show with David Letterman (airing TONIGHT) that she and Joel are ready to tie the knot, according to People.

The couple has two children together – daughter Harlow, 2, and son Sparrow, 5 months.

Congratulations to the happy couple!! Catch Nicole on Letterman tonight to see if we get a proposal story!