"Nervousness is the product of 'The fear of failure'. All your body systems are on high alert when you don't want to fail.
While talking to someone you really admire, you want them to see the best of you, so there is a lot of pressure to present yourself well. Also, the stakes are pretty high for you as compared to talking to other people and that makes the situation even worse.
I won't ask you to be yourself and get relaxed. I believe you have tried that already!"