TikTok and YouTube stars can now join Hollywood's biggest union.

The Screen Actors Guild-American Federation of Television and Radio Artists (SAG-AFTRA) has approved an "influencer agreement" that expands coverage and membership options to online content creators. (The term influencer is interchangeable with creator or content creator.) The terms will apply to individuals who are paid to advertise products on social media platforms.

"The Influencer Agreement offers a pathway for both current and future members to cover their influencer-generated branded content under a SAG-AFTRA contract," the union's president, Gabrielle Carteris, wrote in an e-mail.

There is no minimum follower count for influencers who want to join the union, although eligibility for health and pension plans is based on certain work requirements.

Getting one's "SAG card" has long been code for breaking into Hollywood. (The Screen Actors Guild merged with the American Federation of Television and Radio Artists in 2012). Performers within the union are more likely to get work on a variety of film and TV projects, and it provides many with access to health and pension plans.

Aspiring actors often toil away for months or even years as unnamed extras in order to earn enough credits to qualify. Now, the definition of covered work within the union has expanded to include making sponsored content for brands.

It's the latest sign that the business of influence has become a crucial part of the entertainment industry and a gigantic revenue stream: Brands are poised to spend up to $15 billion on influencer marketing by 2022, up from $8 billion in 2019, according to an Insider Intelligence and Mediakix report.

SAG-AFTRA's new agreement opens membership to more YouTubers, TikTokers, Snapchat stars and anyone else creating sponsored videos or voice-overs. In addition to offering benefits, the union will be able to advocate on behalf of content creators and pursue legislation to serve the creator community. It can also offer assistance with collective bargaining and help settle payment disputes between influencers and the brands that hire them.