In early 2004, Clark was approached by Playboy magazine to pose—clothed—for the cover of the magazine's upcoming May issue. Clark, who came in second place behind fellow Canadian country singer Shania Twain in a poll in the previous year, turned down the offer saying "I think of all the young girls who come to my shows, I think of those faces, I think of my mother, and I worry about the signal [sex] sends to them[…] If I’m sexy enough for Playboy to want me with my clothes on, then I hope the message can be that sexy is about what’s between your ears, in your heart and your smile."
On May 15, 2004, during a performance of the Grand Ole Opry, Clark was surprised by Steve Wariner and her mother Linda with an invitation to join the Grand Ole Opry. Clark was officially inducted on June 12, 2004, and is currently the only female Canadian member of the Grand Ole Opry. Shortly after her induction, Clark's first greatest hits album, Greatest Hits 1994–2004, was issued. The album's only single, "Girls Lie Too", became Clark's first number one in the United States since 1998's "You're Easy on the Eyes". While the song did not reach number one in Canada, it was the named number one country song of 2004 in Canada by Radio & Records. A non-album single, "The World Needs a Drink" (which was co-written by a then-unknown Eric Church), was released in late 2004, but was not included on any of Clark's studio albums.