Our hearts go out to Matt Damon and his family. According to ONTD, Matt Damon’s father is currently battling multiple myeloma.

The actor revealed the news publicly on Wednesday when he and his father, Kent Damon, took part in a benefit for Massachusetts General Hospital.

According to WCVB in Boston, Matt said his 68-year-old father will “fight it to a standstill,” referring to his disease, which is incurable.

Multiple myeloma is an “accumulation of malfunctioning or ‘cancerous’ plasma cells,” according to EmedicineHealth.com.

According to People, Kent’s disease is in remission.

Matt and his father took part in the One Hundred Celebration at the Westin Hotel in Boston, where the actor thanked the medical staff for their help.

“My family is so grateful for the care you’ve given us,” Matt said at the event. “It’s deeply humbling to see how many people here are committing their lives to helping others.”