'The Simpsons' sets TV milestone with 600th episode

The Simpsons celebrated its 600th episode Sunday, making U.S. history as one of the two scripted primetime shows to reach the milestone.

Fox's animated series offered fans a special immersive experience to celebrate its 600th episode on October 16. The episode's famous couch gag was available to view in virtual reality for anyone equipped with the relevant Google gadgetry.

America's longest-running primetime scripted TV series, "The Simpsons" had a very special Halloween episode in store for its viewers. "Treehouse of Horror XXVII" was not only a Halloween special -- an annual tradition for the show since 1990 -- but was also the first ever episode to offer a virtual reality experience.

This 360° VR experience took viewers into the world of the famous yellow family, but not for the entire episode. Viewers were able to experience the famous "couch gag" that has faithfully opened each episode of "The Simpsons" for 28 seasons in VR. The gag, dubbed "Planet of the Couches," was already animated but never used, and was hanging around at Fox waiting for its moment to screen.

Viewers saw a three-minute virtual reality version specially designed for the occasion instead of the 45-second opening ritual in its usual form. Those who Google Cardboard kits also got the chance to explore with Homer, Marge and their kids in a prison cell.

Google even created a limited-edition yellow model for the event, finished with various Simpsons characters. 25,000 lucky fans who signed up for the free special-edition Cardboard viewers got to watch the episode Simpsons-style.

"The Simpsons" made its debut in 1989 on the Fox network, which began airing the show's 28th season on September 25, 2016.

Gunsmoke still holds the record for the most episodes, with 635.