The new venue will be the chef and restaurateur's fourth Mark's Bar, but its first unaccompanied by a restaurant.
Located in the theatre's Dress Circle and Upper Circle Bars Mark Bar will open from 6pm until 2am Thursday to Saturday serving ticket-holders first and then opening to the public from the end of the performance.
A range of cocktails have been created for the new venue including Vic's Punch (Tangier gin, lemon sherbert, lemon juice, soda and fresh mint) and Pharmaceutical Stimulant (Merlet coffee liqueur, fresh coffee, dash of sugar).
Hix said: “I have always been a huge fan of The Old Vic, so when this opportunity arose, I knew it was the perfect location for our first standalone Mark’s Bar. I’m looking forward to enjoying a cocktail during the interval and after the shows.”
The Old Vic chief executive Sally Greene said: "We are thrilled to welcome the genius that is Mark Hix to The Old Vic. Mark’s Bar is going to transform our bars into the coolest theatre cocktail hangout in London. Without doubt the hippest place to be when the lights are down.”
The addition of Mark's Bar at the Old Vic is part of a transformation of the theatre in preparation for the opening of Matthew Warchus' first season as artistic director. Changes include the addition of a new all-day cafe on the ground floor called Penny and a refresh of the front-of-house spaces.
The first Mark's Bar opened at Hix Soho, followed by another at Hix City. Mark's Bar at Hixter at Bankside opened last year.