The planned on and off trade launch of the premium lager follows news of the launch of Guinness Black Lager last week.
Diageo is said to be trying to satisfy the growing popularity of premium imported lager with the launch of Windhoek but will initially target ex-pat South Africans already familiar with the drink.
The drinks maker has secured a deal with Tesco as well as on-trade distribution deals with bars in UK cities including London, Manchester and Brighton.
Diageo’s lager portfolio is smaller than rivals SABMiller and AB Inbev. Its other lager brands include Red Stripe and Harp.
The drinks maker is currently trialling Guinness Black Lager in the on and off trade in Northern Ireland with the aim of a wider European rollout if the test proves successful.
The drink is available in 300ml bottles. The launch is being supported by a marketing campaign.
The drink is the latest Guinness brand extension. Previous efforts have included Breo and Guinness Light.