'Catherine who?' Dad’s Army actress Holli Dempsey recalls her embarrassing faux pas after co-star Ms Zeta-Jones invited her out for dinner

Being asked to dinner by Hollywood royalty is daunting for anyone, but for Holli Dempsey it was so unexpected she had to question who it was.

The actress, who stars in Dad's Army, revealed she was left baffled when she received the invite from her world-famous co-star Catherine Zeta-Jones at the start of filming.

Holli told FEMAIL: 'I didn't know who it was, I asked someone "who's Catherine?" The woman looked at me like "are you joking?"

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Holli Dempsey, pictured at the Dad's Army premiere last week, bagged the role of Pike's girlfriend Vera in the film of the much-loved BBC comedy series

Holli failed to make the connection when she received the message from just 'Catherine' as she wasn't expecting the star to be so friendly.

However she later acknowledged 'she needs to eat like any Hollywood royalty. It was quite a normal thing to do'.

As well as Zeta-Jones, who plays journalist Rose Winters in the film, there's plenty of acting veterans on board, which the Welsh actress had also asked to come to a bonding dinner. 

Based on the much-loved BBC series, Toby Jones plays Captain Mainwaring, Bill Nighy is Sergeant Wilson, Tom Courtenay takes on the role of Lance Corporal Jones - and even the original Pike, Ian Lavender, makes an appearance.

Set in 1944, when World War II was near its end in the fictional town of Walmington-On-Sea, Holli plays Pike's girlfriend Vera who's in the Auxilliary Territorial Service (ATS), 

Holli said: 'She's a really sweet working girl - but be careful how you put that - salt of the earth and quite brave.'

Catherine Zeta-Jones plays a journalist who reports on the home guard, pictured in the film, and was down to earth and invited the cast to dinner

Holli wasn't keen on her outfits which involved a girdle and made her feel like a 'sack of spuds,' pictured with on-screen boyfriend Blake Harrison as Pike

The comedy sees a journalist descend on the town to report on the home guard, until MI5 suspect they are dealing with a spy.

And Holli expressed her relief at taking on a new character introduced especially for the film.

She said: 'The boys have had a lot more of pressure filling the boots of their parts. I had the freedom to make my own Vera.' 

She was teamed with Blake Harrison, who plays Pike but is best known for his portrayal of dim-witted Neil in The Inbetweeners.

However having already worked with Blake before for a TV series, Big Bad World back in 2013, she did not find her 'showbiz boyfriend' too daunting.

Holli said she enjoyed mingling with the many big names on set - once she got over her invite from Catherine that is.

The role brought the A-lister - who is normally based in New York with her husband Michael Douglas and their two children - much closer to her Welsh roots.

Holli started a game of tag with the cast which Sir Tom Courtenay got very into and Holli said by day three it had gotten 'silly'

Holli, pictured in her Auxilliary Territorial Service uniform, made her mum emotional with how similar she looked to her grandma who was also in the ATS

Holli said: 'At some times she had her mum on set occasionally, her family weren't too far away. She can't help [being such a star], she's beautiful and just great.'

And the rest of the cast were game for a laugh too during long hours, mostly filming in Bridlington, East Yorkshire, in the cold and windy weather.

According to Holli, Sir Tom Courtnenay had a particularly playful side.

She said: 'Everyone gets a bit mischievous after a while. I started a game of tag and it really took off with me and Tom Courtney which got a bit silly by day three.

'We were filming a parade scene and I get a tap and he's disappeared.'  

Holli was doubly busy juggling her part in Dad's Army while travelling to London for her role in the Ricky Gervais-penned TV comedy Derek.

Holli was travelling between Yorkshire and London nearly every day as she juggled filming for Derek and Dad's Army and said she felt like a 'shell'. Pictured at the world premiere on January 26

From left, Toby Jones as Captain Mainwaring, Bill Nighy as Sergeant Wilson, Tom Courtenay as Lance Corporal Jones, Bill Paterson as Private Fraser, Michael Gambon as Private Godfrey, Blake Harrison as Pike, Daniel Mays as Private Walker

Holli plays Vicky, a surly teenager who's doing community service at the care home for stealing a pair of trainers. 

She said: 'It was the most frantic time I've ever had. On Monday I'd do Derek, then Tuesday Dad's Army, then Wednesday Derek.' 

'Luckily, Derek finished at 4pm then I was straight on a train. I felt like a shell. I can't sleep on a train. Each job I wanted to be on form but I'm so glad I did both.

However she admitted she had to 'sleep for 48 hours' once filming wrapped up.

Another thing she didn't miss was her Forties-style garb outfit which she felt self-conscious in and wearing a girdle meant it 'took longer than it should' to go the toilet.

But despite feeling like 'a sack of potatoes' she received a much-welcomed boost from co-star Bill Nighy.

She said: 'He told me "Honey there's nothing you could not wear." And when Bill gives you a compliment you take it.'

The actress told how her mother was amazed seeing her daughter in the ATS uniform, as Holli's grandmother was in the service too.

Holli said: 'She was much younger than me while fighting at war. Apparently I look more like her anyway so my mum was definitely emotional.' 

But even in her other role, Holli doesn't get a break in the wardrobe department.

The cast at the premiere with Catherine Zeta-Jones sporting a glamorous dress with a deep thigh split and Holli, second from left, in a black belted dress

Holli plays Vicky, right, in sitcom Derek penned by Ricky Gervais - pictured with Gervais and Kerry Godiman as Hannah, left, and David Earl as Kevin, second left

Speaking of how she turned up to the audition 'in character' to bag her role in the Emmy-award nominated Derek, Holli said: 'I was in a bright-pink hoodie with my hair scraped back on the bus and I could hear these women tutting at me.'

However she was delighted to work for Ricky Gervais as he was happy for the cast to bounce ideas around and even come up with their own story lines.

She said: 'It's nice to be in the room with the man in control but he's working as an equal.

'If you've got an idea you tend to have to go to head office and send lots of emails, but you just ask [Ricky.] And he's just so funny.'

Holli had previously never seen Dad's army before but happily did her homework after her uncle bought her the Box Set. 

But she hopes the film will get a younger generation to discover the comedy which is still repeated on the BBC to this day.

She said: 'I watched it back [for the role] and I've missed out on so much. If people came back and watched the series because of the film that'd be great.'