US President Donald Trump has a bald spot and it evidently annoys him. The former reality television star, who is very aware of his appearance, smirked on Friday when he saw himself on a screen as he spoke to the Conservative Political Action Conference. "What a nice picture that is. Look at that. I'd love to watch that guy speak," said Trump, drawing friendly laughter from a crowd of cheering supporters. Then he seemed to notice a spot on the back of his head with thinning hair. He turned around and moved his hands around his elaborately dyed, comb-over coiffure, seemingly pantomiming the movements needed to assemble it each day. "Oh, boy," he said, facing the crowd again. "I try like hell to hide that bald spot, folks. I work hard at it." "It doesn't look bad, hey, we're hanging in," he added. One more thing to be frustrated about. Trump listed other, weightier issues, that frustrated him in a speech lasting more than an hour, which showed him in full-on campaign mode ahead of November's congressional elections, in which Republicans risk losing control of Congress. He lamented US immigration policies and repeated a story he had used as a presidential candidate comparing unwanted immigrants to a deadly snake. The crowd applauded. Mr Trump's elaborate combing regimen has long been the butt of jokes and speculation. A tell-all book about Mr Trump's White House claimed his daughter Ivanka was in the habit of describing the mechanics of the combover to friends: "An absolutely clean pate – a contained island after scalp-reduction surgery – surrounded by a furry circle of hair around the sides and front, from which all ends are drawn up to meet in the center and then swept back and secured by a stiffening spray." During the 2016 campaign, Mr Trump let a woman tug the hair on top of his head to prove it is attached and allowed Jimmy Fallon to ruffle it during an interview. The president's bald spot was exposed February 2 when he turned away from cameras to climb aboard Air Force One. As Mr Trump climbed the stairs, a wind gust blew aside a flap of hair.