The pop star will kick off her Bangerz world tour in Canada on Valentine's Day, but run-throughs for the show have been thrown into jeopardy after the singer came down with a nasty bug.
Cyrus has detailed her health battle in a series of posts on Twitter, writing: "Up all night to get pukey".
She later added: "I have the worst stomach flu of all time... Regretting all the times I wanted to be grown up as a kid. Someone baby me... everything hurts."
The tour kicks off in Vancouver, Canada.