Add and provide NTAUTHORITY \ NETWORK SERVICE login to SQL 2000 database

I am trying to create a script for CI / deployment purposes, but I am having problems. Unfortunately, I have to use SQL 2000, which is outside my comfort zone.

It looks like CREATE USER ... FOR LOGIN is not supported, so I need to use sp_addlogin and sp_adduser.

I need to grant permission for NT AUTHORITY \ NETWORK SERVICE user:

EXEC sp_addlogin N'NT AUTHORITY\NETWORK SERVICE'
EXEC sp_adduser N'NT AUTHORITY\NETWORK SERVICE'

However, this does not work, since the sp_addlogin call returns an error:

'NT AUTHORITY \ NETWORK SERVICE' is not a valid name because it contains invalid characters.

So how can I do this?