Hollywood actress Catherine Zeta-Jones admits watching her husband Michael Douglas battle throat cancer is the hardest thing.

'The hardest part is seeing his fatigue because Michael was never tired earlier,' femalefirst.co.uk quoted her as saying.

Michael got to know about his throat cancer last month and is currently undergoing chemotherapy and radiotherapy treatments.

Despite admitting that his cancer is at an advanced stage, 65-year-old Michael is confident he can beat the disease, though he is finding the treatment hard.

'It's a fight. It really knocks you out,' Michael said earlier.

The couple has two children together, Dylan, 10, and seven-year-old Carys.

The 'Wall Street: Money Never Sleeps' actor also has a son, Cameron, from a previous marriage.