Christie Brinkley & Alexa Ray Joel on Billy Joel's Separation

Billy Joel and his wife Katie announced earlier Wednesday that they are separating, and ET caught up with Billy's ex-wife Christie Brinkley and their daughter Alexa Ray Joel later that night.

"I was really sorry to hear this news," Christie tells ET. "I wish him the very best. I wish them both happiness in their future. Billy's a great father, and he's been a great friend to me over the years."

The mom and daughter pair hit the red carpet along with Russell Simmons and more stars at the 6th Annual Wayuu Taya Foundation Gala, which raises funds to benefit the indigenous Wayuu people of South America. The night was hosted by model Patricia Velasquez, who founded the Wayuu Taya Foundation