Just do it. Ignore the audience and focus on what you are playing. Immerse yourself in the music and not the audience. If you are thinking about what they might think you are not concentrating on the music. Imagine you are playing behind a curtain as if they can hear you but not see you. A lot of people who struggle to play in public use different tricks to get used to the environment until they are comfortable with the situation. And remember they probably cannot do what you can, so you have the advantage. Above all else ENJOY what you are doing. Good luck.
'The purpose of life is a life of purpose' - Athena Orchard.