Cookie Monster just revealed his real name!

We bet you didn’t know, but Cookie Monster wasn’t always called that.

On Twitter, the famous cookie-munching mascot of "Sesame Street" revealed his real name is actually...Sid! 

“Did you know me name is Sid? But me still like to be called Cookie Monster,” our favorite furry blue Muppet character said.

His real name was first revealed in a “Sesame Street” song from 2004 titled “The First Time Me Eat Cookie.”

“Me was just a mild-mannered little kid. In fact, I think back then me name was Sid,” he sang.

But then he grew to really love cookies, and thus was named Cookie Monster—kind of like what happens in a superhero’s origin story.

In case you were wondering if Sid a shortened version of a longer name, we think yes.

In a 2010 tweet, Cookie Monster said, “Me wasn’t born with name ‘Cookie Monster’. It just nickname dat stuck. Me don’t remember me real name… maybe it was Sidney?”

Cookie Monster: Me wasn’t born with name “Cookie Monster”. It just nickname dat stuck. Me don’t remember me real name… maybe it was Sidney?

— Sesame Street (@sesamestreet) August 10, 2010

In a 2017 interview on Wired, where the “Sesame Street” cast answered the web’s most searched questions, there was the question, “Is Cookie Monster’s real name Sid?”

“Actually, it is,” he answered. “Me real name Sid Monster.”

Now that’s a fun fact for the day.