Two years ago, in the early days of his new CBS gig, Stephen Colbert made a big deal of presenting what he said was an unknown but talented Paul Simon “cover band,” called Troubled Waters. He introduced the lead singer, Alan (“You can call me Al,” he told Colbert), who indeed bore an amazing resemblance to the smaller half of Simon & Garfunkel. And indeed, he was Paul Simon, and proceeded to play a very strong mini-set (pictured). Tonight, Paul Simon is scheduled to appear again – this time, apparently, as himself.