Disclosing second job before starting PAYE job

Hi there,

I'm about to start a new role in the private sector this month, 4 days a week. In the time since I've signed the contract, I've got an offer of paid employment with a second company for 1 day a week, for the remainder of the summer. It's a great opportunity for my career growth, and there is no crossover in the industries (it relates to my expertise for which I am being hired in my PAYE company but there is no competition there - different sectors)

There's a clause in the contract however that states that 'I will not engage in any other work or employment without prior consent from the business'. I don't want to risk starting my new job on the wrong footing so if you had any experience in how I should handle this, and what I need to disclose to my new company, it would be much appreciated. This job opportunity didn't exist until after I signed the contract.

Thanks