Hugh Hefner's Brother Keith Dead at 87

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The Playboy Mansion has lost one of its own.

Hugh Hefner's younger brother, Keith, died at the age of 87 on Friday, ET has confirmed. The Girls Next Door reality star, Playboy exec and occasional actor -- Keith guest-starred on the classic '60s sitcom, Get Smart -- had been battling cancer.

The news comes one day before Hugh's 90th birthday.

Hugh took to Twitter to confirm the news on Friday afternoon, writing, "This morning, my dear brother and best friend passed away. I love you, Keith. Rest in peace."

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first reported the news and say that Keith died at his home in Beverly Hills, California.

Keith's wife, Caya Hefner, has been sharing a number of shots with her husband lately, including a selfie cuddled up together. "You've given me so much love and support!! I'm forever grateful. Love you Keith," she wrote.

"We are having so much fun together," she wrote alongside a Snapchat of Keith using the dog filter.

On Thursday, Caya tweeted an old photo of her with both Keith and Hugh and wrote, "Love this pic of us. A brother in law & a husband that I genuinely love and care very much! #grateful #tbt"

Former Playmate Kendra Wilkinson-Baskett tweeted about the loss, writing, "Just heard the news about Keith Hefner. He was such an awesome guy. I will miss him. #RIPKeith"

The Playboy Mansion has been put on the market for $200 million -- with the requirement that you keep Hugh as a roommate. Find out more in the video below.