The veteran actress also told how she continues to paint despite her failing eyesight caused by a degenerative condition. But she said she remains an optimist who never takes anything for granted.
Dame Judi, 88, is now determined to learn something new every day, and says learning her lines helps with that.
In a wide-ranging interview at a special Christmas edition of I Remember It Well with Gyles Brandreth at the Garrick Theatre, she recalled how her feisty parrot Sweetheart once told her nephew to drop his trousers.
The As Time Goes By star also lamented that she used to urge budding actors to see as many shows as possible to learn from their contemporaries – but now going to the theatre is too expensive.
The most Oscar-nominated British actress in history told Gyles: “I do get nervous but it is not your business to show it to people. That is what I say to young actors.
“Nerves are very, very good for you as they generate energy. But it is not your business to share it with the rest of the company.”
Asked about her philosophy of life, she replied: “I don’t know. I have always been an optimist.
“You should never ever, ever take anything for granted and that is a good philosophy to have.
“The older I get it is important to learn something new every day. I do it with a lot of lines.”
Dame Judi, who went to art school before switching to acting, and was diagnosed with the common condition Age-related Macular Degeneration (AMD) in 2012, continues to paint.
She added: “A blind woman painting I am. I can’t see but I love it.
“I do have an issue with my eyes and it is boring, really boring.
“I used to be good at handstands. Not so much now.”
She also recalled how she once met the mayor of Stratford with theatre director Trevor Nunn and said: “The Mayor was blind and I said ‘How lovely to hear you again’.
“I was so nervous. I thought I said ‘Long time no see”, which is not good is it?’”
Inappropriate sayings can also be heard at her Surrey home.
Dame Judi, who lives alone with her parrot, said: “I had my family over in the autumn.
“I was talking to my nephew and my parrot suddenly said ‘Drop your trousers’.
“She likes me to stroke her beak. I daren’t touch her as she once bit through my finger.
“She doesn’t like it when I paint my nails. I painted my nails yesterday and she backed away and said ‘Don’t offer me a radish’.”
Hitting out at theatre prices, the actress who made her debut at the Old Vic in 1957 said: “I used to say go and see as much as you can, even if it is not the thing you want to do like cabaret or stand-up.
“I used to say to people go and see people do the job and now it is not so easy as it is so expensive.”
Recalling her career she recounted how she once met the legendary actress Dame Sybil Thorndike.
“When I played Juliet at The Vic she came around afterwards and she was wonderful, but she did say ‘I was a bit disturbed that the costumes were dirty’,” Dame Judi said.
“The costumes were broken down as we did look like people in Verona.”
She also met Sir Ralph Richardson, known for his eccentric behaviour on and off the stage, and their meeting proved no exception.
She said: “He said, ‘May I give you a kiss?’ and I said ‘Yes’ and he bit my ear instead.”
She was in the same drama class as Vanessa Redgrave and recalled how they were once “protesting in Trafalgar Square and Vanessa got arrested. She said to the police ‘You can’t take me away as I have got a matinee this afternoon’.”
Dame Judi also looked back at growing up in York with her parents and said: “My father was very adventurous and in 1948 my mother, father and I had a caravan which was half a caravan and we called it L’Escargot.
“We drove from York to the south of France. It was very dangerous but I did not think much about it but it was unbelievable.
“We were going around Versailles and my father used to go around corners saying ‘Oh they have a caravan just like ours’ until he realised it was our caravan.”
The trip must have influenced her as she admitted: “We have got a bidet at home but nobody has ever used it.”
And she recalled how once she needed a wheelbarrow to get home.
She had to pull out of the original 1981 stage production of musical Cats due to injury – but appeared in the much-maligned 2019 film version.
Dame Judi said: “I snapped my Achilles tendon and that was rehearsing for Cats and I remember not knowing how to get into my house.
“So I got in a wheelbarrow and was thrown on the sofa.
“I groan at the mention of Cats.”