Movie star James Woods insists he'll never complain about his woes after meeting motor neurone disease sufferers as part of his preparation for a harrowing role in an upcoming episode of ER.

The actor will play a doctor suffering from Amyotrophic Lateral Sclerosis (ALS), which is also known as Lou Gehrig's Disease, in the medical drama.

And he insists meeting real-life ALS sufferers made him realise there's nothing he can moan about.

He says, "If you ever meet someone fighting ALS and you ever complain about anything, you don't deserve to be heard, honestly. It's just an unbelievably, astonishingly devastating disease."