Roger Federer appears alongside Elmo in a new Super Bowl commercial for the running shoe brand, On, that has them debating which letters are actually on the sneaker.

Roger Federer and Elmo from Sesame Street seem to disagree on the letters of the alphabet in a Super Bowl ad for ON running shoes.

With new episodes dropping every Thursday on the streaming service — and later airing on PBS during the fall — fans can also look forward to a new song ... to ABC, she teamed up with Elmo ...