Oh, sure I did, do and will do!
I'm not much of an actor, although I too had been helping in several plays; mostly minor roles. But funnily enough, back then I was completely calm.
But when I was still playing violin, and we had class performances, I was completely calm until it was my turn to go to the stage and play my piece! As much as I adored the latest pieces I practiced so much with my teacher, be it Thais Meditation, The Girl With Flaxen Hair or The Swan, I would walk to the stage, hand my violin to my teacher to tune the instrument for me and prepare the papers with my notes - and my knees would be shaking the whole time I was playing! I swear the people had to see it, because I felt as if I was barely standing!
As a dancer now I'm usually rather calm - but when we are performing some choreography we finished only few days before the performance and none of us is sure we'll be able to dance it without forgetting what steps are in the next part, I'm nervous as hell; palms sweating, breathes are heaving in my chest and I feel ready to drop with a heart-attack xD But once I'm on stage, I suddenly find myself standing straight, with practiced yet still natural smile and doing the steps without thinking about what I'm doing.
Funny how this works, no?