The LOL star explained the injury via Twitter, telling her followers that her clumsiness was to blame for the incident.
"cracked my tail bone doing a front flip... on to the couch (sic)," Cyrus wrote on the social networking site.
"thats like when i tripped over a pillow and broke my arm. #onlyme," she added.
Cyrus recently unveiled a cover of Bob Dylan's 'You're Gonna Make Me Lonesome When you Go'.
Earlier this month, it was reported that the 19-year-old spent $50,000 to lose 15lbs before a trip to Hawaii with boyfriend Liam Hemsworth.
Watch Miley Cyrus in the trailer for LOL below: