'Riverdale' and '90210' star Luke Perry hospitalized and under observation: Rep

It was unclear why Perry was in the hospital.

"Riverdale" and "90210" star Luke Perry is currently under observation at a California hospital, ABC News has confirmed with the actor's rep.

The cause of the hospitalization was not yet confirmed.

Perry currently stars as Fred Andrews on CW's "Riverdale," a successful take on the famous Archie Comics stories, but his claim to fame was "Beverly Hills, 90210," where he played teen heartthrob Dylan McKay.

Fox recently announced that "90210" is coming back with much of the original cast, but it's not clear if Perry had signed on for the project.

Jason Priestley, Jennie Garth, Ian Ziering, Gabrielle Carteris, Brian Austin Green and Tori Spelling are all returning for the six-episode series, airing this summer, which is called "90210."

"Beverly Hills, 90210" premiered in 1990 and aired for 10 seasons. In 2008, The CW launched a spin-off, also called "90210." The show featured a new cast, but also included appearances by the original actors. It ran until 2013.

After news of Perry's hospitalization hit, many took to social media, including current and past co-stars to wish him the best.

"Sending my love to Luke Perry," Molly Ringwald wrote.

His "90210" love interest Shannen Doherty also spoke out.

"My friend. Holding you tight and giving you my strength. You got this," she wrote.

Ian Ziering added, "No words can express what my heart feels hearing today's shocking news. Let us all say a prayer for his speedy recovery."