Richard Bacon is suffering pneumonia across both lungs.
The 42-year-old radio presenter was taken off a plane and put in a wheelchair before being rushed to hospital, and was later diagnosed with double pneumonia.
He wrote on Twitter: "Thank God I got ill in Britain (actually on the way to Britain, was taken off the plane in a wheelchair). F**k all the ideology driven politicians who've messed up America's healthcare system. Viva the NHS. Happy 70th. (sic)"
In response to BBC News presenter Rachael Bland asking if he is OK, the former 'Blue Peter' presenter replied: "Basically pneumonia. But across two lungs. I'll be here a few days. (sic)"
But Richard admitted he was surprised to have been diagnosed with the inflammatory condition of the lung, because he has always associated it with older people.
He tweeted: "I looks lve got pneumonia. Although I thought that was for people in their 80s (sic)"
This comes just four months after Richard revealed he had been diagnosed with attention deficit hyperactivity disorder (ADHD).
He recently said: "Mental health problems are usually not something you can physically see, so you might assume that ADHD is purely psychological, not something which shows up on a scan.
"But the type I have can actually be seen. I have lower blood flow to the front of the brain, the part called the pre-frontal cortex.
"If you look at my scan it looks a bit like there is a hole at the front of my brain.
"It initially made me think that some of my brain was missing, like I had half a brain - that would explain a lot."
But Richard - who was infamously axed from children's TV show 'Blue Peter' in 1998 after he took cocaine - admitted he loves having an "impulsiveness" for life.
He said: "In many ways I like having ADHD. I have an impulsiveness and a love of life - every day I wake up and feel like I'm about to have the best day of my life."