The Barenaked Ladies, who wrote and recorded the theme song for The Big Bang Theory, explained the story behind the song.

Band members Ed Robertson and Tyler Steward told CBS that writing the theme song was really fun.

The Barenaked Ladies were asked to do the song by the show’s producers, who were big fans of their band. The producers called them up to ask if they would write the theme song for the new sitcom, which first aired in 2007.

Robertson explained how it happened, “Just by coincidence, I had just finished a book by Simon Singh about big bang theory, about cosmological theory, so I made up a song in the show about cosmological theory and these guys were developing the show… They looked at each other… and said we’ve gotta get these guys to write the theme song.”

The producers loved the Barenaked Ladies and their song so much that they even invited them to visit the set several times.

The Big Bang Theory, which stars Kaley Cuoco, is currently in production for its 7th season, according to TheBigBangTheory.com.

Watch the Barenaked Ladies performing the theme song live at Comic-Con, below.

Photo: CBS