Director of another company while Sponsored on Tier 2 General Visa

I am sponsored by a company on a Tier 2 General Visa.

I have a business opportunity to acquire a share of a small business and become a shareholder and director of this business.

The new business is not in the same category as my sponsor company.

I will not be employed by the new business, I will only be a shareholder and director of the company doing a few admin tasks.

By becoming a director and shareholder of this new company, am I in contravention of UK immigration law and will this jeopardize my ability to apply for ILR in future?