Your  no claims bonus should still build up as normal, providing neither of you have an accident.
But if you or your named driver has an accident, it’s likely to affect your bonus. That’s because, regardless of who’s driving, you’ll be making a claim and your insurance provider may need to pay out.
Policies hardly ever allow your named driver to build up a no-claims discount of their own. This is worth bearing in mind if you’re adding a  young driver  to your insurance, as they won’t typically receive a no-claims discount until they take out a policy in their own name.
However, your insurance provider may offer the young driver a discount to take up a policy with them, based on their driving history in your car.