unclear on National insurance

Hi, I am employed full time but have taken on a side gig and will manage my own billing and taxes. I am unclear on whether I should pay additional NI on this side hustle (+8k a year). I am already inthe higher tax rate. Do I need to set up as a sole trader or should I just submit my earnings? Thanks

Hi

Yes.  Your 'side hussle' does not appear to be through employment, which means that it is self employment.  
As your turnover is more than £1000, you are required to register for self assessment, as self employed.  
When you declare your profits and expenses, self assessment will factor in the Class 1 National Insurance deducted by your employer, when calculating the Class 4 National Insurance arising from your self employment.  
Any tax and national insurance that arise from your completed tax return, will be collected through self assessment.  Please see Register as a sole trader.

Thank you