RICKY GERVAIS breaks taboos like politicians break promises. The holocaust, paedophilia, bestiality, the killing fields of Cambodia: just a few of the topics up for discussion in his latest stand-up show, Fame.

But instead of bodyswerving a comic who draws laughs from so-called "no go" areas, people have flocked to see him and his tour has packed out arenas and theatres around the country. Newly returned from appearing in front of an audience of 5000 in New York's Madison Square Gardens, Gervais is about to notch up a personal and Fringe Festival first, when he performs at Edinburgh Castle on August 26.

Between weekend touring, writing the Christmas special of his comedy series Extras and preparing for his first Hollywood leading role in the movie Ghost Town, Gervais will round off the Edinburgh Fringe in style, performing in the open air to 8000 in the biggest ever one-man show at the festival.

"Playing a castle, eh? I can't wait," said Gervais, en route for another performance. "It is the first castle I have done a gig at, though I have stayed at a few as we like to stay out from the centre of towns. In fact, I am getting used to castles, which is scary. How I've changed.

"It will still be essentially a comedy gig where a lot of people will see me at once. It is certainly an event for me, if not for them.

"I have never done open air before, though I've appeared before at things like Live Aid, which doesn't really count. But I don't know how people can sit in the outside for an hour. There might be owls, there might be storms. That worries me."

Westlife, Cliff Richard and Donny Osmond to name but the corniest, have all performed at the Castle. But until now, it has been thought too huge to work as a venue for stand-up comedy.

Gervais has performed at the festival three times, including once as part of a troupe alongside The Office co-writer Stephen Merchant, comedian Robin Ince and 8 out of 10 Cats host Jimmy Carr. However, his last visit was far from enjoyable.

Gervais said: "I tried to go out but it was a nightmare as Extras was on the telly and I was at the biggest festival in the world. Everyone was lovely but I couldn't walk a yard without someone asking for a picture. I ended up sitting in my hotel room watching the cricket, so you know I was desperate.

"I genuinely really enjoy Scotland. I started the tour there this year as Glasgow and Edinburgh were the best dates for me on my Politics tour; I love them both as cities."

Despite his affinity with the country, with his brother now living here, he doesn't plan to stint on the insults. "I do a joke," he said, "where I say my friend said I shouldn't go to Scotland as they hate the English and I say well that's a cliché. He goes the trouble is they are all just alcoholics and I went bollocks, loads of them are smackheads as well."

One Scot he does speak reverentially of is Billy Connolly, who was among the audience when Gervais appeared in New York in May. Afterwards, Connolly declared Gervais showed "some kind of genius in human observation". Gervais admits the thought of the best stand-up comic in the world watching him did little to ease the nerves.

"He was great," added Gervais. "I had never met him before and I wanted to tell him how good I think he is, but not be that guy who embarrasses him.

"He was very nice to me, though I don't believe him! I would be lying if I said it doesn't mean a bit more coming from someone like that - the flattery is tenfold.

"I told him, I want to be where you are,' at a place where you can walk on stage in front of thousands and be as funny as you are in the pub. That has always been my aim when I was on radio, on TV, on chatshows. He has always been at that point."

The pull of America remains powerful for comedians and Gervais has proven very popular, thanks to the success of the American version of The Office. But while Connolly opted to set up home in the US, Gervais is happy just to visit, planning an extensive tour next year.

Describing his recent performance in New York, he said: "I don't get nervous live but I was nervous there only because it was my first thing in New York and everything was going so well in America - I didn't want this folly to be the end of it. I certainly got away with it in that respect.

"I love America and New York in particular. I love what they have given me, but I love England as well and even enjoy paying taxes."

David Bowie, who appeared in the second series of Extras, introduced Gervais in New York with a rendition of Chubby Little Loser, the song he first performed on screen to describe Gervais's character in the show, Andy Millman. So who then to better Bowie for his bow at the Fringe?

"It has got to be the Krankies," said Gervais, referring to Scottish comedy duo of Janette and Iain Tough, before considering Janette's fall, while performing as Wee Jimmy, from a pantomime beanstalk. "Is she better now? I heard she fell out of a tree. Or is that Keith Richards? Why are people falling out of trees, that didn't happen in my day. Do you know it's a she dressed as a boy? I don't know how that started."

Gervais continued: "I will be angry if it rains - the thing about weather is it makes me angry and it makes me angrier that there is no-one to blame as I'm an atheist. You can't get annoyed at no-one, I need someone to fire.

"All you can do with weather is hope. I tell you what, is there any way this new SNP fella could put me in charge of weather? If you believe in God you should put someone in charge of weather, just a priest or vicar to pray. And if you are an atheist, bring an umbrella."

Tickets for Gervais's Fame show at Edinburgh Castle go on sale tomorrow

host of booker winners to attend international festival

Less literary, but equally celebrated attendees, include Jeremy Paxman, his former political sparring partner William Hague, writer-explorer Benedict Allen and cookery writer Clarissa Dickson-Wright.

For Kelman, who turned 60 last year, it will be the first appearance since 2004, the year he published his last novel, You Have To Be Careful In The Land Of The Free. Barker, meanwhile, has a new novel, Life Class, out next month and Atwood published a poetry collection, The Door, earlier this year.

William Hague will be appearing in support of his recently published life of William Wilberforce, whose campaigning led to the abolition of the slave trade in 1807. It follows the former Conservative Party leader's 2005 biography of William Pitt the Younger.

Hague's fellow biographers Claire Tomalin and Tim Jeal will talk about, respectively, Thomas Hardy and Henry Morton Stanley, who uttered the immortal line: "Dr Livingstone, I presume." Or did he?

As well as James Kelman's presence, Scottish fiction is well served with William McIlvanney, Andrew O'Hagan, and James Robertson all putting in appearances. Scottish poets in the programme include Carol Ann Duffy and Don Paterson.

Still on the poetry front there will be much interest in the appearances of Zadie Smith's husband Nick Laird (on the bill alongside the Anglo-Indian winner of the Forward Prize for Poetry, Daljit Nagra); Simon Armitage, who has written a new translation of Sir Gawain And The Green Night; and Tony Harrison.

The straight-talking Harrison, a Yorkshireman like Armitage, celebrated his 70th birthday this year by winning the Wilfred Owen award for poetry. Neither of those events is likely to dampen his enthusiam for a spat, however. He has proved a trenchant and vocal critic of the Iraq war and his Edinburgh appearance is likely to be one of the sparkiest.

Also on the book festival schedule are celebrated cyber-punk author William Gibson; Marina Lewycka, author of the best-selling A Short History Of Tractors In Ukrainian; playwright and author Michael Frayn; and rising star Hari Kunzru, who featured alongside Zadie Smith and Monica Ali in literary magazine Granta's 2003 list of the best young British novelists.

Gibson and Kunzru have new novels published in the UK at the end of August. Gibson's novel Spook Country deals with smuggling and espionage and is set, in the author's words, "in the same universe" as 2003 novel Pattern Recognition.

Kunzru's new novel returns to the themes of identity and reinvention which were at the heart of his impressive 2002 debut, The Impressionist. Called My Revolutions, it tells of a middle-aged man whose life is rocked by the emergence of a former acquaintance from his days as an armed revolutionary in the late 1960s.

Other writers appearing include memoirist and novelist John Lanchester and travel writer Tobias Jones. In the children's author strand are Michael Rosen, Herbie Brennan, Philip Ardagh and Graham Joyce, who writes for older children.

The book festival's full line-up will be announced on Thursday. The festival runs from August 11-27