It is estimated at £50,000-£70,000.
The picture, Pears, was painted in 1994 when Watt had a studio at London Fields in Hackney and it depicts one of her favourite models.
Ms Watt said: "She was strong, fiercely intelligent, intuitive and as an artist herself, she was demanding to work with."
Pears dates from her first period of commercial success when her canvasses often depicted the female form in large, light-filled settings.
Chris Brickley, head of pictures at Bonhams in Scotland, said, "Pears is a major picture by Alison Watt whose paintings rarely come to auction."
Festival City Theatres Trust, which runs major venues in Edinburgh, has released its annual report. It reports a 4% increase in tickets sold at the King's and Festival Theatres and a 27.9% increase in ticket income.
Friends membership revenue has increased by 86% on the previous year, and the activities it programmes in learning and participation have risen greatly, by 262% .
The review, which recaps activities from April 2012 to March 2013, also includes a summary of Scotland's first 'relaxed performance', held at the Festival Theatre in December 2012, and updates on the refurbishment of the King's, environmental policy and new theatre programmes.
The Cupar Arts Festival will feature 40 artists and features the theme of 'fate' in a series of unconventional venues across the Fife market town. Artists are participating in the biannual arts festival from as far afield as Japan, Taiwan and Italy in the event from October 5-17.
The festival places art in non-gallery spaces around the town including: a former grain silo, the railway station, the town's medieval alleys, churches, county buildings, a former jail, vacant shops, the local park and Hill of Tarvit Mansionhouse.
Artists include Anthony Schrag, Kirsty Whiten, Caroline Dear, Colin Andrews and Wounded Knee. The main visual arts programme is complemented by music events from FOUND, Kid Canaveral and Withered Hand, a member of Fife-based King Creosote's Fence Collective.
This is the fourth Cupar Arts Festival.
An EKOS report says the overall economic impact of the Merchant City Festival on Glasgow was valued at £916,420, up 5% from last year.
The report found that that 98% of people questioned rated the festival as very good or good. It noted that 17% of visitors were from outside of Scotland, with all of these festival-goers rating the quality of the city as a tourist destination as either very good (68%) or good (32%).
The 2013 Merchant City Festival took place between July 24 and 28 and was the 12th annual festival.