US dancer and choreographer Michael Flatley, famous for his Irish production Riverdance, has had surgery for an "aggressive form of cancer".
A post on his Instagram page said he was "in the care of an excellent team of doctors", adding no further comments would be made.
Flatley, 64, shot to fame with Riverdance, which first appeared during the 1994 Eurovision interval in Dublin, lasting seven minutes.
Flatley had choreographed it.
Its success at Eurovision, where it teamed Irish dancers with music by Bill Whelan, saw it extended into a full-length show which opened at Dublin's Point Theatre the following year.
The Riverdance 25th anniversary website suggests that since its debut, more than three billion people worldwide have seen the show on television.
Flatley, born to an Irish-American family in Chicago, has also created, produced and directed productions including Feet Of Flames and Celtic Tiger.
He has previously had a diagnosis of facial skin cancer which he was treated for in 2003.
He also directed and starred in the spy thriller film Blackbird, which did not receive many positive reviews.
The film also starred Eric Roberts, Patrick Bergin and Ian Beattie. Flatley played former MI6 operative Victor Blackley, who returns to the world of espionage, having left it behind.
Last year Flatley also launched a Lord Of The Dance tour, which helped raise money for the humanitarian effort in Ukraine.
-BBC