Irish-American dancer Michael Flatley has "an aggressive form of cancer" and has had to undergo surgery, according to a statement on his Instagram account.
The 64-year-old dancer and choreographer was catapulted to fame in the Irish dancing production Riverdance, which was first performed as a seven-minute interval break in the Eurovision Song Contest in 1994.
The post on Flatley's account said: "Dear friends, we have something personal to share, Michael Flatley has been diagnosed with an aggressive form of cancer.
"He has undergone surgery and is in the care of an excellent team of doctors.
"No further comments will be made at this time.
"We ask only for your prayers and well wishes. Thank you. Teamlord."
After the success of Riverdance at Eurovision, it was extended into a full-length show and opened at Dublin's Point Theatre in 1995.
Flatley, who was born into a blue-collar Irish-American family in Chicago, followed up with his own stage show, Lord Of The Dance.
He has also created, produced and directed other productions including Feet Of Flames and Celtic Tiger.
Flatley's shows have played to more than 60 million people in 60 countries and have grossed more than $1bn (£823m).
Last year, Flatley also launched a Lord Of The Dance tour to raise money for the humanitarian effort in Ukraine.
He has also expanded into film, directing and starring in the 2018 spy thriller Blackbird.