You see, George Clooney *was* there and he *did* reprise his role as Dr. Douglas Ross, but rather than being joined by his former E.R. cast, it was House’s Hugh Laurie who showed up. (And yes, he was completely in character.)
As Kimmel began experiencing organ failure, Laurie pushed Clooney to “give him the rapper’s delight!” and he did just that as he began busting out the 1979 hit.
“I said a hip hop, the hippie to the hippie, the hip hip a hop, and you don’t stop, a rock it, to the bang bang boogie, say up jump the boogie” he rapped, trying to bring the beat back to Kimmel’s heart. Of course it worked.