Can i use an electrical socket to supply power to a new light?

i am putting a new light into a walk in closet and i want to know if its ok to connect into the existing plug socket in order to supply power to the light. i am running the cable from the plug socket to the new light switch and then from the switch to the light fitting. the plug socket has two sets of cables connected into it already so im thinking its not a spur and so it should be ok to use?