Casey Affleck ended up chewing his own tongue after a traumatic experience at the dentist's surgery.

The 37-year-old actor felt like he had a ''lightening bolt'' travelling from his brain to his mouth when the dentist took a ''gigantic needle'' to his mouth, accidentally striking a nerve.

Speaking on 'The Tonight Show with Jay Leno', Casey said: ''They said they'd numb it up a little bit then they took out this gigantic needle and put it in. At first it was like this little pinch like when you usually get Novocain at the dentist.''

''And then, I'm not exaggerating, it felt like a lightning bolt had gone from the top of my brain out to my tongue. I screamed, which I wasn't happy about and the dentist said, 'Oh, I must have hit a nerve, I'm sorry'. It turns out he struck a nerve with the needle.''

Casey - whose brother is actor-and-director - headed to lunch shortly afterwards, where he ended up chewing on his tongue ''like it was part of the meal'', because his mouth was still numb and he couldn't feel anything.

He added: ''I couldn't feel anything but I still needed to eat. I noticed there was some blood on my food.''

''This is kind of gross, sorry, but I realised I'd been chewing on my tongue. I had no feeling in my tongue so I was chomping on it like it was part of my meal!''