From Longman Dictionary of Contemporary Englisha fully paid-up member of somethinga fully paid-up member of something informalCERTAINLY/DEFINITELYif someone is a fully paid-up member of a particular group, they strongly support what that group likes or believes in a fully paid-up member of the celebrity circuit → paid-up
Examples from the Corpus
a fully paid-up member of something• Thus, Milwaukee-based guitarist Daryl Stuermer became a fully paid-up member of the Genesis live auxiliaries.• Are you now a fully paid-up member of the new economy?• At the moment I would describe him as a fully paid-up member of the politically embarrassed tendency.• Listen to that big-mouthed gilgul, acting like she's a fully paid-up member of the team. 