Depends on the cover afforded by either policy. If you give permission for someone else to drive your car, they must have the extension of other use to drive other vehicles on their policy. Otherwise, no cover would be in place. If they have it, they would be covered to drive your car third party only on their own policy.This would not cover any damage to your car.

If you want cover in place to cover your car, and not just for any third party claim made against you or your friend, then you would need to put them on as a named driver on your policy, or they would need to add your car on their policy.