Christie Brinkley is a doting mom to three adult children, and she was particularly proud of daughter Alexa Ray on Tuesday.MORE: Christie Brinkley displays all-natural beach look for important reasonAlexa Ray, who is the daughter of Christie and singer Billy Joel, is an accomplished singer and recently released some new music.And taking to her Instagram, Christie helped her daughter promote it, by sharing two clips.WATCH: Christie Brinkley and her children dance together on ThanksgivingThe first