Elvis attended Ann Margret's November 28, 1972 Midnight Show on her comeback** opening night at the Hilton - Here he is Leaving the Hilton after the show early on November 29, 1972 - ** The reason for the comeback was that on Monday, September 11, 1972, while performing at Lake Tahoe, she fell 22 feet from an elevated platform to the stage and suffered injuries including a broken left arm, cheekbone, and jawbone. She required meticulous facial reconstructive surgery that required wiring her mouth shut and putting her on a liquid diet. Unable to work for 10 weeks, she ultimately returned to the stage almost back to normal.

Thanks to Doc at FECC for the details