B1 and B2 guests at Varuna's first Blue Mountains Writers' Festival in August

Varuna, the National Writers' House, will host their first Blue Mountains Writers' Festival in August and B1 and B2 are expected to be popular guests.

The Bananas in Pyjamas will "literally be coming down the Katoomba library stairs", said Varuna's executive director, Veechi Stuart, resplendent in pyjamas, dressing gown and ugg boots at the library recently, to advertise the occasion.

The Banana Pyjama Party is on Saturday August 24 from 4.15-5pm and 5.15-6pm. Tickets are $6 for children (under 12 months and parents are free).

"The first event has already sold out with 40 children coming," Ms Stuart said. "This will be a very special Blue Mountains Writers' Festival Pyjama Party and we hope the grown-ups dress up too."

The icons of Australian childrens' television first appeared on TV screens on Play Schoolin the 1970s. The Bananas visit is just one of more than 30 events taking place in locations including Varuna, the Carrington Hotel, the Blue Mountains Cultural Centre and Katoomba cafes and galleries around Katoomba.

The four-day writer's event will run from Thursday, August 22, to Sunday, August 25.

Featuring a festival launch party, some of Australia's best writers in conversation, a kids' day, as well as poetry by the fire pit, a visit to Darks Cave, music, book clubs and a program of writing workshops, the event will have something for everyone.

Celebrated authors on the line-up include Kerry O'Brien (stepping in for Stan Grant), Wendy Harmer, Markus Zusak (The Book Thief), James Valentine, Tim Flannery and Melina Marchetta (Looking for Alibrandi). Varuna has a stellar alumni, including 2019 Stella Prize winner, Vicki Laveau-Harvie, who is also part of the festival.

Varuna's creative director Amy Sambrooke said older children might enjoy a visit with author and stand-up comedian Oliver Phommavanh, author of Natural Born Loser and more in a free session on Saturday August 24 from 2pm.