If the talks are successful, it is thought that Stonegate may look to convert some of the sites to its Slug & Lettuce brand.
Last month, the Ian Payne-chaired group announced plans to nearly double the size of its Slug & Lettuce estate and it is believed to have earmarked a further 65 outlets for the brand across the UK.
Slug & Lettuce currently operates 72 sites, having experienced three years of double-digit like-for-like sales growth.
Earlier this year Premium Bars & Restaurants (PBR), the owner of the Ultimate Leisure nightclub business, appointed advisors to explore options for Living Room, including a possible sale, after receiving several approaches from funds interested in investing in, or purchasing a stake in, the bar and restaurant brand.
The group appointed Zolfo Cooper Corporate Finance to explore options for the business after significant interest was also shown in the 13 former Ultimate Leisure sites, which were placed on the market earlier this year.
It is thought that Living Room, which has been managed by Eclectic Clubs & Bars since August last year, has seen strong trading on the back of a raft of new initiatives.
Its estate includes sites in London, Liverpool, Manchester, Glasgow, Edinburgh and Bristol.
PBR announced a successful refinancing in February, which saw debt reduced from £63.1m down to £20m, as well as the strategic decision to market some of its Ultimate Leisure sites for sale, with a view to re-investing a proportion of the released capital back into the business.
Living Room was founded by Tim Bacon in 1999 and became an iconic brand, with its original Manchester site frequented by footballers and other celebrities.
The business was bought by Ultimate Leisure in 2007 for £28m. Orchid took over the management of the business in 2009.
All parties declined to comment.