The 82-year-old singer cancelled his show in Budapest on Tuesday.
Tom's wife of 59 years Linda Trenchard died in 2016 after being diagnosed with lung cancer.
The 80-year-old crooner won huge praise for his performance, but also sparked a lot of conversation for a much sillier reason.
Les penned more than 60 hit songs during his decades-spanning career.
He will go ahead with a scheduled performance on Friday.
'He is determined to be back performing very soon.'
'The condition is being well managed and we are hoping for a speedy recovery.'
Anne-Marie, Shawn Mendes, Kylie Minogue and... Sting & Shaggy?!
It's all about one 16-year-old boy this year.
There's just one thing standing in his way.