Nervous as I am of organising parties, I could hardly have launched a book about friendship without throwing one. And so it was that last Tuesday night, I found myself in the Owl Bookshop in Kentish Town, north London, surrounded by those pals of mine who were good enough to trog through the rush hour rain to celebrate with me.

The Virago Book of Friendship is the result of a year’s work and a lifetime’s reading – and as an anthology, it’s a bit like a party itself, Virginia Woolf cosying up to Sarah Waters in one corner, and Shirley Conran chatting to Charlotte Brontë in another. Nora Ephron, whose laugh may be heard over the crowd, is moving around the room with a tray of canapés, Edith Wharton is wondering why the champagne isn’t premier cru, and Colette’s about to go outside for a cigarette.

As the book’s editor, I had rather more to do than rush around refilling glasses. So many shelves ransacked! People have asked if I have a favourite extract, a question that’s hard to answer: I’m devotedly fond of everything in it. But if I had to choose one piece, it would be an account by the American scholar Terry Castle of her doomed friendship with the writer Susan Sontag. I challenge you not to laugh out loud at the vignette in which Sontag relives her experience of sniper fire during the siege of Sarajevo in 1993. This she does during a visit to Stanford University in California, on Palo Alto’s chi-chi main drag, bobbing zanily from Restoration Hardware to Baskin-Robbins while pointing all the while at imaginary gunmen on rooftops and gesticulating wildly at poor old Castle (“Our relationship was rather like the one between Dame Edna and her feeble sidekick, Madge, or possibly Stalin and Malenkov,”) to encourage her to keep up.

Star struck by Van Gogh

A delicious feeling at the National Gallery as I slipped a barrier and quietly stepped inside a preview of its new exhibition Van Gogh, Poets & Lovers.

A once-in-a-lifetime experience, it will surely be sold out for as long as it runs, and yet here I was, unimpeded by any hubbub, the only sound that of two well-known male art critics extravagantly saluting each other. When I emerged some time later into the crowds who were making their way to the cafe and the shop, I felt smug – and just a little bit odd. I thought of Mr Benn, in the 70s children’s TV show, whose visits to a fancy-dress shop result in adventures appropriate to his costume, after which he then returns to boring old real life. I had seen things – so many things – and they had touched me. But now, like everyone else, I was on the hunt for a cup of tea and a postcard.

Carpeted by a critic

On Friday, The Critic, starring Gemma Arterton and Ian McKellen, opened in cinemas across Britain. For me, this is beyond thrilling: the film is based on a novel (Curtain Call) by my husband, and the thought of audiences seeing his name as the titles roll makes me feel a bit tearful.

But while the premiere, held at the Curzon Mayfair a few days before, was incredibly glamorous, especially for two people who spend most of their time alone, it was also somewhat of a meta experience for me. I was afraid that an actor whose recent series I’d likened in a review to a moth-eaten waxworks would recognise me. Had this happened, one of the more furious scenes from the movie, set in London’s theatre land in the 1930s, might have played out for real on a 21st-century red carpet.

• Rachel Cooke is an Observer columnist

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