Liam Payne, Harry Styles and Bert Sing the Alphabet on ‘Sesame Street’ [Video]Liam Payne, Harry Styles and Bert Sing the Alphabet on ‘Sesame Street’ [Video]Just when we thought One Direction couldn’t get any more adorable, the British-Irish boy band stopped by 'Sesame Street' and brought it to a whole new level.Mandi SalernoMandi Salerno