Martha Stewart's younger sister, Laura Plimpton, has died after suffering a brain aneurysm at her home on Tuesday, Aug. 5. She was 59-years-old.

News of her death was announced via an email sent to staff at Martha's lifestyle company, where her sister had served in a senior role.

"My youngest sister, and the youngest of the six Kostyra siblings, Laura Kostyra Plimpton, passed away today in Norwalk Hospital," the email read. "Laura worked for me and the company for more than 25 years."

laura plimpton

Via themarthablog.com

Martha goes on to explain how her sister had felt unwell after her morning workout and was rushed to the hospital by her husband, Randy. Calling Laura, "the very best," the 73-year-old describes her as "an extraordinary employee, mother, wife and sister."

The businesswoman also shared that her sister's organs had been donated. "We are so sad but also happy that Laura had the foresight to donate so many healthy organs to needy people," she wrote.

The pair have always been close, with Laura citing Martha as a mother figure when they were younger. After her first husband died from cancer, Martha helped the mother-of-three find a home and offered her a job.

Along with being involved in the day-to-day running of Martha Stewart Living Omnimedia Inc., Laura also wrote scripts for Ask Martha radio spots and appeared in segments.