Former Goodies star Bill Oddie has revealed he has been suffering from an "almost fatal" condition this summer.
The 79-year-old conservationist and birdwatcher used Twitter to tell followers he had been "very ill" with "lithium toxicity".
He wrote: "Just so you know, I have been very ill most of this summer. Lithium toxicity. Almost fatal!
"I am still here but very confused about most things! But then aren't many of us.
"IT fuddles my brain. Confusion. Will I return? I Really dunno. I do hope so. Please wish me luck. XX."
The TV presenter had last tweeted on June 22.
According to the NHS, lithium is a type of medicine known as a mood stabiliser.
Too much lithium in the blood can trigger serious side effects, including causing people to lose their appetite and feel sick, lightheaded, drowsy or confused.
It can also lead to blackouts, shaking, muscle weakness, blurred vision and difficulty speaking.
Oddie found fame in the 1970s as a member of comic trio The Goodies, alongside Tim Brooke-Taylor and Graeme Garden.