The Miracle Worker star, 68, shared the news with fans via Twitter earlier this week (begs08Jun15), but revealed she is determined to remain positive about the health crisis.

She wrote, "Mike has been diagnosed with prostate cancer, surgery June 30. I know he will be ok, but many unknown factors now".

Duke was flooded with sweet messages from followers after going public with her family's troubles and the former child star has taken the time to repost many of the tweets online.

Replying to one user who assured Duke "everything will be all right", she wrote, "Thank you friend. We know it will."

Duke wed Pearce, her fourth husband, in 1986. They have a son, named Kevin, while Duke is also mother to actor Sean Astin and his half-brother, MACkenzie.