Since opening in 2013, Golden Boy has been an influential, thriving force in Adelaide’s dining scene. While the city has changed significantly around it (the small venue licence was introduced in Golden Boy’s debut year), the modern Thai restaurant remains among the industry's finest.

Six years on, business is booming (co-owner Sondra Deering says this year’s Fringe season was the busiest yet). So much so, the restaurant has had to merge with the adjoining Botanic Bar, which now operates as a second dining room, to meet demand.

“Everyone wanted to start dining in the bar,” Deering tells Broadsheet. “We got to a stage where we were booking out the booths, but then you might get a large crowd of people and it disrupts the [dinner] experience so that’s when we made it all table service. But in that we lost having a cocktail bar … so that’s what we’re bringing downstairs. It’s satellite Botanic Bar in a way.”

The 50-capacity cellar, to open mid-June, will be a place to grab a pre or post-meal tipple. Until recently it was storage space for Golden Boy and Africola next door. Before that it was leased by East End Cellars to hold its top-shelf wines.

With a gorgeous new interior conceived by designer Claire Markwick-Smith of UFO Agencies (her newly launched design company with James Brown and Golden Boy co-owner, Deering’s husband, James Hillier), the once dusty brick cellar has transformed into an intimate basement bar with soft apricot walls, plush blue carpet and brass detailing. When Broadsheet visits, power tools are going full throttle but we can already see it’s going to be a stunner. The main wall, where several leather booths (similar to those in Botanic Bar) will be installed, features foliage-like detailing delicately handcrafted with concrete plaster.

“We tried to preserve some of the old [brick] but with all the electrical we had to put in there would have been conduits all over the place – so we had to cover it,” says Deering. They also had to install toilets, air conditioning and lighting. “It just became a bigger and bigger project and we thought, ‘Do we [really] need it?’” admits Deering. “But [the restaurant] keeps getting busier and busier. We’re sending [customers] down the road a lot – and sometimes it could be for 10 minutes – to grab a quick drink.” The bar will act as a holding area of sorts where diners can imbibe before dinner.

“We hear a lot, ‘Where can we grab a quick drink?’ and ‘Where can we find a private dining area?’” Deering continues. Helpfully, you’ll now find both downstairs. The team is introducing a private dining room for up to 20 people next to the bar. A sprawling marble table (like those found upstairs) will be the setting for a high-end version of the restaurant’s popular “tuk tuk” menu, which puts you in the hands of your server. The concept is so popular the room is already booked out for its first month of trade. A second kitchen has also been installed for cooking prep, freeing up some much-needed space upstairs.

Golden Boy’s basement bar will open mid-June. Keep an eye on Broadsheet for updates.