Richard Branson announced on Tuesday that Joan, his wife of 50 years, has died. She was 80 years old.

Branson shared the news on his Instagram account, writing that he was “heartbroken.”

“She was my best friend, my rock, my guiding light, my world,” he wrote.

The billionaire entrepreneur, who founded the Virgin Group, added that Joan was “the most wonderful mum and grandmum our kids and grandkids could have ever wished for.”

This is a developing news story; check back for updates.