If you are leaving your current job to join another one in another company, especially with an altogether different job profile, then here is how you can state this fact in your resignation letter. Keep it simple and there is no need to go in detail about your new job.
Change of Career Resignation Letter:
Dear [Your Boss Name]
I communicate my decision to end the working relationship I have with the company since June 2010. The decision is strictly based on professional grounds since I am making a shift to a different domain. As you might be aware, I was always interested in building a career in dance and music; and recently I happened to get this opportunity in the form of an offer from [Name of the company/organization].
[Date], [Day] will be my last working day in the company.
I thank you for the career opportunity you gave me, and the good working environment that has characterized the company over the years.