Miranda Hart was a "gibbering wreck" when she hosted 'Have I Got News For You'.
The 39-year-old comedienne admits she doesn't normally get nervous while starring on TV but she felt particularly anxious about being a guest presenter on the BBC One quiz show until it was over and she could relax.
She said: "Hosting 'Have I Got News For You' turned me into a gibbering wreck. But I could laugh about it right after it had happened so I'm getting confident about how to get over my under-confidentness."
While Miranda tries to stay calm during her TV appearances, the 39-year-old actress was recently star-struck when she met her idol, legendary tennis player Martina Navratilova.
She added to Tatler magazine: "I actually met my idol this year - Martina Navratilova. I was very nervous then. The person who introduced us overdid it and said I was hilarious and Martina said, 'Hello - are you going to do something funny?'
"I should have said, 'Are you going to do a serve?' But I panicked and said, 'I nearly dropped my tea earlier.' And then there was a silence. And my upper lip started to sweat. So I said, 'Ahem, by the way there's this thing in the UK called Comic Relief and they do sketches and then there's this sister charity called Sport Relief and again they sometimes do sketches but you wouldn't know it in America because it's UK-based but in one of the sketches I played tennis against Tim Henman at the Albert Hall.'
"And then there was another pause. And I sweated a bit more. And she wandered off. And I thought, 'I've just said the phrase 'sister charity' to Martina Navratilova.' Even Richard Curtis would have told me to shut up."