The chain, which is also up for sale, blamed the move on the “significantly more challenging environment” caused by the pandemic.
PizzaExpress has said it could close around 67 of its UK restaurants, putting up to 1,100 jobs at risk.
The chain, which also revealed it has put itself up for sale, blamed the move on the “significantly more challenging environment” caused by the coronavirus pandemic.
Highlighting the “current unprecedented backdrop” of COVID-19, bosses believe reducing the size of the business will help protect the majority of staff.
The threat of closures, first revealed by Sky News last month, are the latest sign of the pain being felt by by hospitality industry, which has been hard-hit by the public health crisis.
The company said it plans to launch a company voluntary arrangement (CVA) restructuring deal in the near future, which could lead to the closure of 15% of its 449 UK restaurants, threatening up to 1,100 posts.
However, it insisted the final outcome had “yet to be decided”.
Pizza Express said it has also hired advisers from Lazard to lead a sale process for the business.
The firms closed all its UK restaurants on 23 March after the government-ordered lockdown, aimed at curbing the spread of infection.
Andy Pellington, group chief finance officer, said: “While we have had to make some very difficult decisions, none of which has been taken lightly, we are confident in the actions being taken to reduce the level of debt, create a more focused business and improve the operational performance, all of which puts us in a much stronger position.
“We can now plan to invest in both our UK&I and international businesses as well as support our teams as they return to work.”
Zoe Bowley, UK and Ireland managing director, said: “Our business has a long history of success, but the UK-wide lockdown has hit the hospitality industry particularly hard.
“While the financial restructuring is a positive step forward, at the same time we have had to make some really tough decisions.
“As a result, it is with a heavy heart that we expect to permanently close a proportion of our restaurants, losing valued team members in the process.”
She added: “As we continue to reopen our restaurants for dine-in and delivery, we will successfully navigate the extended period of social distancing expected in the months ahead and, in so doing, protect 9,000 jobs.
“The initial signs from the restaurants that have been reopened have been very encouraging and we hope that our loyal customers continue to support us now more than ever.”