WASHINGTON (Reuters) - Garth Brooks donated a smashed guitar to the Smithsonian Institution on Tuesday, but the country-music superstar turned into a wide-eyed tourist when he saw the company he would be keeping.

Wearing his signature black cowboy hat, the singer eyed a pink outfit worn by Patsy Cline and Judy Garland's ruby red slippers from "The Wizard of Oz" before signing over his patched-up guitar, a Stetson hat and a gold record to the Smithsonian's Museum of American History.

"I always thought that when this happened you'd feel like Elvis, and I don't," said Brooks, who has largely retired from performing. "It's funny being the person that's in here, because never, ever do you think you can measure up to the people who are already in here."

Brooks has sold 123 million albums over the course of his career, making him the top-selling solo artist in U.S. history. Only the Beatles have sold more albums.

His catchy singles like "Friends in Low Places" and high-energy, rock-style shows propelled country music to the mainstream during the 1990s.

Brooks' donated memorabilia include a stage outfit and hand-written lyrics to "The Beaches of Cheyenne," but it is his Takamine guitar that is likely to attract the most interest.

The guitar became a touchstone of his career when it was smashed at a 1991 Dallas concert that was taped for television. It has since been reassembled, minus several pieces that have been auctioned off for charity.

The items will go on display in January at the Smithsonian's "Treasures of American History" exhibit, which is housed at the Air and Space Museum while the American History Museum undergoes renovation.

Other items in the exhibit include Irving Berlin's piano, Louis Armstrong's coronet and Thomas Edison's lightbulb.