Second job as self employed

Hi HMRC admin, I have a full-time job as a junior doctor, and I do my self-assessment every year. However, I have recently started doing some extra shifts as a locum for a private hospital. They paid me fully, and they told me that I needed to sort out my taxes. Can I be self employed for this private work and do I have put this self-employment income through self-assessment or I need to file separate tax for the self-employed income? or I should setup a limited company for the private work ? I'm a bit confused about what to do...thank you

Hi aah2024,
As your private work is not taxed at source via PAYE, you will need to register for Self employment (as a Sole Trader) to declare this income.
Once you have registered, you can declare this income in your usual Self Assessment return, by completing the Self Employment pages (while still declaring your regualr PAYE income in the Employment pages).
To register as a Sole Trader, go here:
What a sole trader is
Further guidance can be found here on how to complete your Self Assessment tax return.
HMRCgovuk
Or for more advice, contact us by webchat or phone here:
Self Assessment: general enquiries
Thank you.