It happened at Manhattan's Apollo Theater late Thursday, when Obama stepped to the podium and veered from prepared remarks to thank Green for warming up the crowd.
Apparently not content with simply praising him, Obama suddenly launched into Green's "Let's Stay Together," starting with the vibrato "I'' and pausing for enthusiastic applause before finishing up with the line "so in love with you."
Obama said his staff didn't believe he'd really do it.
Then he joked that the Sandman hadn't come out - a reference to Sandman Sims, the tap dancer who chased unpopular acts offstage at the Apollo for decades.
Online: http://apne.ws/x7ak4B
