Britney Spears had a cameo appearance as a love-struck receptionist on hit TV show “How I Met Your Mother.” Although her performance was well-received, it has been claimed her co-stars struggled to work with her because she refused to take off her sunglasses until the cameras started rolling. A show insider claimed: “Britney delivered her lines, but the show’s actors had a tough time reading her expressions since they couldn’t see her eyes at all.”"It’s hard for an actor to make a connection when all he sees is his own reflection staring back at him in shiny dark glasses, but no one wanted to upset Britney by asking her to take them off.”"In the end, someone said to her, ‘You will be taking the sunglasses off for the actual tapings, right?’ To which Britney responded, ‘Uh…right!’”