Primark is investing £100m into stores this year, with its sites in Oxford Street and Stratford set for a revamp.
The budget retailer said 700 new jobs will be created in 2024 as a result of new stores and extensions.
Its Westfield Stratford store will almost double in size to more than 81,000sq. ft to become the second largest Primark in the capital.
Meanwhile, its site on Oxford Street will receive a refit. Primark said it is jazzing up its stores to mark 50 years on the British high street.
Kari Rodgers, UK retail director at Primark said: “We’ve changed a lot in the fifty years since we opened the doors on our first store in Great Britain in Derby back in 1974, but at our heart, we are still the same.
“We’re as committed as ever to offering the very best value on the high street and making great fashion more affordable and accessible for everyone.
She added: “This latest investment will mean bigger and better stores, hundreds of new jobs across the country and shows our ongoing commitment to the UK high street.”
The retailer employs more than 30,000 people in the UK and has 192 stores in cities and town centres, as well as shopping centres and retail parks.