Viharn Lai Kam (The Gilded Assembly Hall) is a hall where the Phra Singh Buddha is housed. It is an attractive building of Thai Lanna Style, 24 metes wide and 56 meters long.

The teak temple is a beautiful example of Lanna or northern Thai architecture, with soaring "wings" on the ends of the eaves and lavish carved wood and stucco decoration throughout. The walls inside the temple are adorned with paintings depicting Lanna life in the 19th century. The mural paintings on the walls of Wat Phra Singh depict the scenes of Suwannahong and Sang Thong classic literature.

This hall was built by the royal command of King Borom Ramadhibordi in B.E. 2369 (AD 1726) but remained unfinished. Later it was completed by the royal command of King Pharmakanka and restored by Phra Upalikunupamajarn inB.E. 2469 (AD. 1953)