No one was injured in the event which occurred while one of the 'Bangerz Tour' coaches was travelling along a highway in the US on Monday night (17 March).
Miley's younger sister Noah broke the news via Twitter, posting an Instagram video of a burning bus at the side of a road – and then the charred remnants.
"Bus down!" she tweeted.
Watch Noah's video of the fire below:
Thankfully, no one was hurt in the fire, with Noah assuring fans: "Everyone got out safe. No one is injured whatsoever. Everything is okay!"
According to TMZ, the destroyed bus had been carrying Noah and Miley's mother Tish between concert venues, while E! News reports that all the duo's belongings were destroyed.
It's believed the fire was sparked after a tire burst.
Miley's last concert was in Houston, Texas on Sunday, 16 March, with the next stop scheduled for this evening in New Orleans, Louisiana.
The singer hasn't directly referenced the fire herself but did retweet one of Noah's messages that simply said: "Cyrus bus down!" The tweet was accompanied by several flame emoticons.