Just when you thought One Direction couldn't get any more adorable—how much can the human heart take, after all?—this happens.
Hold on tight! Harry Styles and Liam Payne joined Bert of Bert & Ernie fame to sing the Alphabet. There's a bit of a fumble during the performance which, you know, is just so incredibly endearing.
This isn't the boys' first trip to Sesame Street. Remember when the group sang about the letter "U" to the tune of "What Makes You Beautiful"? Check it out here.
Watch the darling clip above!