Michael Jackson's Doctor spoke to Anderson Cooper from his jail cell last night on CNN.

Conrad Murray not only spoke to Cooper via phone, he also sang to Coop. 

Murray did not really reveal much as the hook to the interview was the wrongful death suit filed by Jackson's mother Katherine.

The interview was the usual crap until  it turned really weird.

Murray starts singing over the phone to Cooper, ​belting out his version of "The Little Boy That Santa Claus Forgot."

The look on Cooper's face as he starts signing is priceless. ​

Here's the video:​