Billy Joel sings 'Uptown Girl' to ex-wife Christie Brinkley at recent Madison Square Garden concert

 Billy Joel is still singing to his "Uptown Girl," Christie Brinkley.

A recent video from Billy's Madison Square Garden concert has gone viral, showing his ex-wife Christie dancing along as Billy sings his 1983 hit, Uptown Girl.

The video shows Christie and a friend dancing along on the big screen for the whole audience to see. She looked up at the stage, presumably at Billy, as he sang.

The video was captioned, "40 years later and your ex man is still grinning at you like that while he sings the song he wrote about how rich and hot you are?"

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In a 2010 interview Billy confirmed that while he originally began writing the song about several women, he eventually became focused on Christie.

"I started dating Christie, and rather than it being about all these different girls, she became the uptown girl," he said at the time.

She also starred in the 1983 Uptown Girl music video.