The Tony Award winner, 67, has revealed she was out riding on her Texas ranch when her horse lost its footing, and she was tossed to the ground.

Buckley tells New York radio station WBAZ she fractured five vertebrae in her lower back, but reveals her doctor is "quite positive and very optimistic" about her recovery, adding she is "healing really fast".

The Broadway veteran is still planning to hit the stage in August (15), when she stars in a New York production of musical Grey Gardens, which centres on the reclusive aunt and cousin of former U.S. First Lady Jacqueline Kennedy.

Buckley jokes that she's taking method acting to the next level, since her real-life character, Edith 'Big Edie' Bouvier Beale, spends most of the show in bed.

She says, "I can't believe the universe goes to such detail to try to prepare me for a part, because there was no reason for this accident with this beloved horse of mine."