LOS ANGELES: Nicole Richie and Joel Madden are engaged. Capping a Valentine’s weekend in style, Richie announced during February 15’s taping of the Late Show With David Letterman that, after three years of courtship, two children and one confused lawyer, she and her rocking beau are finally ready to walk the aisle. The Late Show episode is set to air on February 19. There was no immediate comment from their rep, and the duo has yet to tweet out the good news. Richie, 28, and Madden, 30, have been planning their wedding before the birth of daughter Harlow in 2007. Apparently with the birth of son Sparrow last September; the couple figured it was time to ramp things up.