Sesame Street’s Elmo turned 3-and-a-half Feb. 3, despite being introduced on the show in 1980. Here’s the reason why his age stays so specifically fixed.

Elmo is turning 3-and-a-half, his age forever and always, since he joined "Sesame Street" in 1980. Of late, he's become a social media sage.

Consider yourself Elmo, celebrating your third birthday... once more. We are beginning to believe that this little red furball has figured out the secret to eternal youth.

More characters can be seen during the Sesame Street Party Parade ... and the singing of “Happy Birthday” to Elmo at the iconic 123 Sesame Street stoop. Just for Kids Weekend and Elmo ...