Getty Images

Watch One Direction Adorably Sing Their ABCs On 'Sesame Street'

Now you know your ABCs.

You know what's the best? When little-kid nostalgia and One Direction are paired together. Kind of like that time they covered Wheatus' "Teenage Dirtbag."

It’s not always likely, but when it happens -- like in this new clip from "Sesame Street" -- it's a joyous occasion. This time around, Liam Payne and Harry Styles take on the ABCs.

Behold, the 1D guys lazily lolling the alphabet with Bert:

This isn't One Direction's first time on the PBS program. Back in January, all five of the guys sang the praises of the letter "U" to the tune of "What Makes You Beautiful."