Adele Parks & Jane Fallon: 'I was worried I'd be scared of her because of the way the heroines are in her books: ballsy, arsey, in your face'

The two authors both write about feisty heroines in the same genre, but say they aren't in competition with each other

Parks, left, says: 'Jane is a lot shyer than me; I'm very enthusiastic and upfront and tell it as it is. In our friendship we play out different roles for each other' (Jean Goldsmith)

Adele Parks, 46

Having worked in advertising and as a management consultant, Parks (left in picture) published her debut novel in 2000. She has since become one of the UK's biggest-selling women's fiction writers, with more than three million books sold. She is also an ambassador for literacy charity the Reading Agency and supporter of the National Literacy Trust. She lives in Guildford with her husband, Jim Parks, creative director of the Guildford Book Festival

When Jane had written her first book [Getting Rid of Matthew, in 2006], her agent sent me a copy and asked me to come up with a quote for the cover, if I liked it. After I read it, I thought, oh my goodness, it's better than a best friend's diary – it's like reading a worst enemy's diary. I emailed that to her and she was like, "Oh my god, that's what I wanted people to think!"

Sometimes with debut books the author is not that different to the leads in the book, so I thought, I hope she's the tough one not the wet character in Getting Rid of Matthew. I think Jane was worried that I was brash and harsh, like some of my characters. But we met over lunch and discovered that we are both gentle people who highly value trust, and from then on we've met regularly for lunch.

Jane is a lot shyer than me; I'm very enthusiastic and upfront and tell it as it is. In our friendship we play out different roles for each other – I'm like the Pollyanna character with happy tassels, while she plays the less optimistic one, with a drier sense of humour.

We've met in New York a few times. Jane and Ricky [Gervais, her partner] have an apartment that they let me and my husband stay in, and it's near a cute pet shop. So we'll have lunch and then Jane and I will go down to the shop to play with the puppies and kittens for hours, as we'll both be missing our cats.

She's a worrier: she worries about her cat, who's never been outside, and worries about health and safety stuff a lot more than me.

We've been to a few of Ricky's gigs, at Hammersmith [Apollo] and Wembley [Arena] and so on. Jim and I are good to have in the audience, as we laugh out loud a lot. I'm often shocked by Ricky, though – my mouth is wide open. We've been to a few of his film premieres and glitzy after-parties in LA, too.

While we both write about feisty heroines in the same genre, we both believe that we are not in competition with each other. It's unusual in a paranoid industry that we can talk plots and not worry if the other is going to steal our ideas. In fact, we don't agree on books. I'll say an ending is sweet, and she'll say, "Actually, it's quite saccharine and I'm not keen."

Calling our books "chick lit" narrows the audience – no bloke is going to pick it up – and is dismissive of the reader and writer. And I'm 46 and Jane is in her fifties – we are not chicks! It never comes up with male writers such as Tony Parson and Nick Hornby – no one defines who would read their books.

Jane Fallon, 55

A former TV producer, Fallon worked on series including 'Teachers' and 'This Life' before turning to writing. She has since written five novels. She lives in north London with the comedian Ricky Gervais and their cat, Ollie

Before we first met I was worried I'd be scared of her because of the way the heroines are in her books: ballsy, arsey, in your face. I thought she'd be loud and pushy.

We have the same agent, and when my first book came out, he sent the book to her for a quote. She was someone I'd always admired; she'd had seven books out by then. I sent an email to thank her for the quote – no one ever does, apparently – and we ended up meeting for lunch and got on like a house on fire.

I invited her to my book launch. I loathe being the centre of attention but I had to make a speech; I blushed and stuttered my way through it. I'm sure she thought I was an idiot, but she was sweet about it. And then we started having lunch whenever we could, and we go to spas to talk about writing and stuff.

Adele's a people person, I'm not. She's also one of the most optimistic people I've met – I'm drawn to people like that, who radiate positive energy. The only downside is that her very enthusiasm sometimes makes me realise how unenthusiastic I am, and I envy it and am wary of it in equal measure.

There's something special about meeting a friend in a place you'd not ordinarily see them. We've ended up in New York at the same time together, and wandered around, before going to sit in the café by the boating pond in Central Park, where I like to go to write.

We've spent time together in LA, too, where Adele and her husband came to the first gig Ricky did there, at the Kodak Theatre. But my overriding memory is of Adele hiding behind our friends all evening. When she's nervous, she worries she'll say stupid things, and she was scared she'd say something inappropriate to one of the glitzy guests.

There are few people I feel I can let my guard down with, but Adele has given me loyalty, and a feeling that I can talk about everything with her if I'm having a hard time. I've got a very thin skin when people say unkind things. But Adele is great, as she'll say something like, if you're nice to people and they don't like you, it's their problem.

The only thing we disagree on is books: we just don't like the same ones. Even the one place we meet in the middle – Fay Weldon – we can't agree on which of her books is best.

Adele knows I'm not a fan of historical novels, so when she started writing one herself [her new book, If You Go Away, is set after the First World War], she was nervous to tell me, as I've often ranted about how I have problems with, say, trying to depict characters who were living in the 14th century. But I loved it.

'Strictly Between Us' by Jane Fallon (£7.99, Penguin) is out on Thursday. 'If You Go Away', by Adele Parks (£7.99, Headline), is out now