Everything we know about the death of the Beverly Hills, 90210 and Riverdale star.

Actor Luke Perry, best-known for his role on Fox's Beverly Hills, 90210, has died at age 52 after reportedly suffering a massive stroke in his California home last week.

“Actor Luke Perry, 52, passed away today after suffering a massive stroke,” read a statement from Perry’s rep. “The family appreciates the outpouring of support and prayers that have been extended to Luke from around the world, and respectfully request privacy in this time of great mourning. No further details will be released at this time.”

Paramedics are said to have responded to a 911 call on the morning of February 27 and then transported Perry from his Sherman Oaks home to a nearby hospital, where he remained "under observation" until he died on Monday.

His stroke occurred the same day that Fox announced a Beverly Hills, 90210 reboot, though Perry wasn't set to return to the cast as famed character Dylan McKay. His most recent role was on the CW's Riverdale as Fred Andrews, Archie's father.

Many are mourning Perry on social media, including his Beverly Hills, 90210 castmate Ian Ziering (who played Steve Sanders). "I will forever bask in the loving memories we've shared over the last thirty years. May your journey forward be enriched by the magnificent souls who have passed before you, just like you have done here, for those you leave behind," Ziering wrote on Twitter.

Perry's Riverdale costar Molly Ringwald, who plays his character's ex-wife, said her heart was broken. "I will miss you so much Luke Perry. Sending all my love to your family," Ringwald wrote.

Joss Whedon, the creator of Buffy the Vampire Slayer, recalled the first time he met Perry, who played Pike in the 1992 film. "Funny, committed, and always gracious. He shouldn’t be gone," Whedon wrote.

So what exactly is a stroke? It's is a reduction in blood supply to the brain due to a blockage or bleeding, and it's often called a "brain attack." When the brain is deprived of oxygen, brain cells die. As a result, a person can lose critical functions, such as memory, mobility, and muscle control.

Rapid treatment—within three hours of the first symptom—is crucial. However, many people don’t realize they’re having a stroke as it's happening, according to research from the University of Oxford.

Symptoms come on suddenly and include difficulty speaking, confusion, weakness, numbness, vision problems, a severe headache, trouble balancing or walking, and paralysis on one side of the face or body.

Stroke risk increases with age. In fact, every 10 years after age 55, stroke risk nearly doubles, according to the American Stroke Association. However, roughly a third of Americans hospitalized for strokes are younger than 65, reported the Centers for Disease and Prevention (CDC). Strokes are actually on the rise in younger people, according to the American Heart Association. That's likely due to a rise in certain health factors, such as hypertension, which is a major risk factor for stroke.

If you're worried you or someone you know could be suffering a stroke, dial 911, and don't hesitate; the quicker the person gets treatment, the better their outcome might be. Also, be wary of doctors misdiagnosing a stroke as an ear infection or a migraine. Ask specifically, "Why do you think it's not a stroke?" If their answer doesn't seem to make sense, get a second opinion.