The chain is responsible for Rooftop Film Club, Cine-Gigs, Drive-In Film Club, Office Club and The Bussey Rooftop Bar and Kitchen.
Belt & Braces was founded by Phil Savage in February 2014 and handled a project brief for the Rooftop Film Club summer series in partnership with British Airways. This is the first time Experience Cinema has brought in an external agency.
Experience Cinema co-founder Gerry Cottle Jnr said: "The team at Belt & Braces stood out for us as enthusiastic, passionate and, above all else, they like to do things a little differently.
"We look forward to working closely with them to highlight the many exciting cinematic experiences we have happening this summer and beyond."