ALEXA RAY JOEL was so furious with the way her stepfather Peter Cook treated her mother, supermodel Christie Brinkley, she decided to write a song to vent her feelings. Cook was caught cheating with his 19-year-old assistant this summer (06) and Brinkley subsequently kicked him out of the house. Joel, whose father is Billy Joel, shares a very close bond with her mother and was inspired to write the song NOW IT'S GONE based on the scandalous affair. Alexa, 20, is starting her own music career and has released an EP with six of her songs on it. She says, "The song is about my anger towards Peter regarding the situation. The lyrics came pouring out. "It was the best release, because for a while I had such pent-up anger and I was just so frustrated and confused. I just wanted to let go of it and release it and that song just really did that for me. "(Brinkley) is such a great mother and I think she takes such pride in her children. I just hope that I can keep making her proud. There's no better feeling than making your parents proud."