You can sell millions of albums, fill stadiums and become one of the biggest stars country music has ever produced—and still not be a member of the Grand Ole Opry.

That surprises a lot of country fans.

Opry membership isn’t automatically awarded when an artist reaches a certain level of success. Artists are invited to join, which is why the list of performers who have never been members includes some genuinely enormous names. A newly updated rundown from Taste of Country counts more than 30 notable country stars who aren’t Opry members.

That’s because the Opry is different from an awards show or Hall of Fame.

Membership represents an ongoing relationship with the institution. The Opry considers an artist’s connection to country music, career and willingness to remain involved with the show—not simply record sales or chart positions.

It also explains why an artist can perform on the Opry stage without actually belonging to the Opry family.

That distinction is part of what has kept membership special for generations.

Since beginning as a radio broadcast in 1925, the Grand Ole Opry has become one of country music’s most enduring traditions. Today’s shows can put a young artist making an early Opry appearance on the same bill as a performer whose career stretches back decades.

And when an artist does receive that famous invitation to become a member, the reactions are often emotional—even from people who have already won awards and played some of the biggest venues in the world.

Maybe that’s the best evidence that, after more than a century, the Opry still means something.