Actor Patrick Dempsey suffered depression on the set of his new movie Enchanted - because he felt desperately out of his depth making a semi-animated movie.

The Grey's Anatomy star struggled acting alongside imaginary creatures, and doubted his acting abilities for the first time in his career.

He says, "It was a real challenge. There's a scene where birds are coming in, and I'm reacting: `Was it big enough or is it too big?'

"I'd go home and be completely depressed because I was like, `Am I making this movie work?' It was like, `Please just let me go back to Grey's Anatomy.'" (IG/TS/MT)

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