Dustin Hoffman and Judi Dench had great fun on set of Roald Dahl’s Esio Trot

Dame Judi Dench and Dustin Hoffman are “human Tiggers”.

It’s hard to picture a veteran Shakespearean actress and a heavyweight Hollywood leading man bouncing about on set full of mischief.

But that’s the view of Dearbhla Walsh, who directed the Oscar-winning pair in the heartwarming tale Esio Trot, which was based on Roald Dahl’s book.

Shown on BBC on New Year’s Day and out on DVD next week, Esio Trot tells how Hoffman’s Mr Hoppy woos Dame Judi’s Mrs Silver.

She’s worried her tortoise isn’t growing, so Mr Hoppy gives her a special incantation to make him grow while secretly replacing him with ever-bigger tortoises.

“Judi has such a sense of fun. She’s quite naughty and she and Dustin together were like two teenagers,” reveals Dearbhla.

“They were very serious about their work and wanting to do the best possible job, but always joking and with such a sense of fun.

“They were like human Tiggers! They laughed so much and Dustin is a real comedian.

“He loves telling funny stories and in another life I think he would love to be a comedy actor.”

Really? He has such a serious reputation as a method actor.

Laughs Dearbhla: “I spoke to an editor who’d worked with him and he said: ‘Oh, God, not him!’

“He’d call on Sunday and you’d spend hours on the phone going through everything because he was full of questions and worries and concerns that he won’t find the character ‘Have you cast the right person? Am I him?’

“And people say they find Judi intimidating, too, but she has a habit of when you speak to her, she’s not someone who fills a vacuum.

“She’s somebody who pauses for a moment and that can be intimidating and you think: ‘Oh my God, she thinks that was the most stupid question you ever asked.’

“But she just thinks before she speaks. She doesn’t waffle, she listens and so the answers have substance.

“She speaks when spoken to, which I think gives her this royal, quite Dame-y feel.

“But she’s so not a Dame she gets really angry about it.

“She doesn’t want you to address her as Dame even at the end when I was thanking her and called her Dame Judi, she just gave me this look she doesn’t like any of that at all.

“They obviously wanted to do those parts. The producer gave me a copy of the email Dustin sent after he read the script, she framed it and I have it in my office and it says: ‘Yes, a thousand times yes. Dustin.’ Isn’t that so sweet?

“Judi’s response was: ‘I must play Mrs Silver, nobody else can play her, I must play her’ and I think it’s wonderful they saw something in the characters because they could work with any big-name director on any film they wanted.”

Dame Judi may have been keen on the role but she still laid down two conditions. She only works a five-day week, and she has to sleep in her own bed each night.

“The lady’s a Dame for a reason!” laughs Dearbhla.

“Where she is in her life, she deserves to sleep in her own bed and having spent a couple of days rehearsing with her in her home, I’d quite like to be going home to there as well!”

Esio Trot is released on DVD by Universal on March 30.