Martha Stewart is mourning the loss of her sister, Laura Plimpton, who died from a brain aneurysm on Tuesday, Aug. 5, reports E! News.

The 59-year-old’s death was announced in an email sent to employees at Stewart’s lifestyle company, where Plimpton worked alongside her famous sister for more than 25 years.

“My youngest sister, and the youngest of the six Kostyra siblings, Laura Kostyra Plimpton, passed away today in Norwalk Hospital. Laura worked for me and the company for more than 25 years,” Stewart wrote in the email obtained by the Daily Mail.

According to Stewart’s email, after her sister fell ill, she was rushed to the hospital by her husband, but doctors were unable to save her.

Plimpton is survived by her three children and was described by Stewart as “an extraordinary employee, mother, wife and sister.”

While the loss of her sibling is a tragedy, Stewart also wrote: “We are so sad but also happy that Laura had the foresight to donate so many healthy organs to needy people.”

Plimpton was an ardent supporter of her sister during her 2004 imprisonment on a federal insider trading conviction and, according to the New York Daily News, when Plimpton appeared on CNN’s “Larry King Live” in 2004, she spoke of Stewart’s generosity and the “very special relationship” they had.