Name

Louise: Welsh

Irvine: Welsh

Date of birth

Louise: February 1, 1965

Irvine: It’s unclear. 1951, 1958 and 1961 have all been quoted as possible years of birth. His official website sheds no light either, stating ‘he remembers little of the birth, though his mother assured him later that it was fairly routine’

Place of birth

Louise: London

Irvine: Leith

Where did they grow up?

Louise: Edinburgh

Irvine: Edinburgh, too; specifically, Muirhouse

Are they related?

Apparently so. In 2012, Irvine Welsh told men’s fashion journal Mr Porter: ‘her great-great-grandad and my great-grandad are the same person. And Louise’s mum and my mum are good friends’

Alma mater

Louise: University of Glasgow

Irvine: Heriot-Watt University

Where are they now?

Louise: Glasgow

Irvine: Chicago and Miami

Before becoming a writer ...

Louise ran a second-hand book shop on Byres Road in Glasgow’s West End

Irvine was in a punk band in London, became a property speculator and then later worked for Edinburgh Council

Number of novels published to date?

Louise: Six

Irvine: Nine

First novel

Louise: The Cutting Room (2002): a riveting literary crime masterpiece with lots of graphic sex

Irvine: Trainspotting (1993): do we really need to tell you?

What the critics said

Louise: ‘The Cutting Room is a hugely commendable debut, assured and memorable. Crime fiction may have its prize-winner at last’: The Independent

Irvine: ‘Welsh writes with a skill, wit and compassion that amounts to genius. He is the best thing that has happened to British writing for decades’: Sunday Times

Most recent book

Louise: A Lovely Way to Burn (2014): set in pandemic-stricken London, the first in her Plague Times trilogy

Irvine: The Sex Lives of Siamese Twins (2014): trademark filth, but this time in Miami rather than Scotland

What we said

Louise: ‘A solid, pacy murder-mystery, A Lovely Way to Burn will keep you hooked to the last page, even if it is unlikely to linger in your mind afterwards’

Irvine: ‘Not even the Miami sunshine can diminish his darkly twisted view of the world. Female narrators authored by men can often fall into clichéd traps but they dazzle in this hugely entertaining read’

Other notable titles

Louise: Tamburlaine Must Die (2003), Naming the Bones (2010), The Girl on the Stairs (2012)

Irvine: Filth (1998), Porno (2002), Skagboys (2012)

Any page-to-screen adaptations?

Louise: A film version of The Cutting Room, starring Robert Carlyle, was in the works for a while but has yet to emerge

Irvine: Most famously, Danny Boyle’s Trainspotting (1996) and most recently, Filth (2013) starring James McAvoy. There’s an adaptation of Porno in the works too, with Boyle directing once again

When they’re not at Charlotte Square, where will you find them?

Louise: At The Empire Café, a series of events that explore Scotland’s relationship with the North Atlantic slave trade. Part of Festival 2014, it’s being held at the Briggait in Glasgow from 24 July to 1 August

Irvine: Probably tweeting. Despite only having joined Twitter in February 2012, by June 2014, he’d already clocked up over 37,000 tweets. That’s a rate of about 44 tweets a day

What else are they up to?

Louise: She’s written plays in the past, and even a libretto. You’ll sometimes hear her presenting radio programmes too

Irvine: Currently, he’s co-writing Higher, HBO’s upcoming sitcom about EDM DJs. Other names being connected to the show include Jay-Z, Will Smith, Jada Pinkett Smith and Calvin Harris

On Scottish independence

Louise: ‘I think whatever happens there’ll be a big stooshie at the end’

Irvine: ‘I think it’s inevitable it will happen. Whether it’ll happen this year or not, I don’t know. It’ll be a close-run thing’

Dialogue 1: Commonwealth (with Louise Welsh), 10 Aug, 7pm; Louise Welsh, 12 Aug, 6.45pm
Irvine Welsh, 22 Aug, 9.30pm
IDP2043 Part 2 with Denise Mina, Irvine Welsh and Friends, 23 Aug, 8.30pm.

All events at Charlotte Square Gardens,0845 373 5888, £10 (£8).