The four-piece alternative/indie band, who have performed at T in the Park, The Edge, Wickerman and Belladrum festivals, will play the venue on Friday, November 30 as the finale of the series of 'The Front Room' events - a joint venture between Lamp House Music and East Lothian Council.
The band are currently touring Scotland and this month support Feeder at the O2 Academy in Glasgow.
They have also supported the likes of Idlewild, Twin Atlantic and Frightened Rabbit, and have played to sell-out audiences at the likes of Edinburgh's Liquid Rooms and Glasgow Garage.
They have a new single and debut album planned for spring 2013.
Supporting Fatherson are popular local band Victorian Trout Conspiracy, who normally play ska as a 12-piece, as well as a local youth act.
Martin Simpson, Lamp House Music spokesman, said: "Even before they went on sale, we had lots of enquiries at Lamp House Music about these tickets.
"Fatherson have a massive following, lately they've been playing on a much larger scale - enormous tents and festivals - so it'll be a real treat to see them play an acoustic set in such an intimate setting.
"The Front Room as a whole has been a great success and it's fitting for Fatherson to provide the finale. It's going to be a top, top night!"
Tickets costing £8 are available from Haddington Library at the John Gray Centre (01620 820680) or Lamp House Music (01620 825630) and on the door, subject to availability.
The bar opens at 7pm with the first band on at 7.30pm.
For more information visit www.facebook.com/frontroommusic