The offer starts at 12pm tomorrow (April 9) at the new Hackney shop in Amhurst Road, ahead of its official opening the next day.
The free lunch will include a choice of a veggie, vegan, or meaty option, plus a bag of Pret’s own crisps and a bottle of juice.
The first customer will also receive a 12-month Club Pret subscription, offering 50% off up to five barista hot or iced drinks a day for a year.
The new shop, which will provide seating for 30 people, is set to create 13 jobs.
Pret A Manger plans to donate all unsold food at the end of each day to local charities through The Pret Foundation, which works to combat homelessness and hunger.
The shop’s menu, featuring favourites like the chicken caesar bacon baguette and the humous and falafel mezze salad, will be freshly prepared daily.
Customers can also try new items like the British sausages, Pret’s baked beans and egg pot for breakfast, or the beef and horseradish baguette for lunch.
The opening hours of the new Hackney shop will be Monday to Friday from 6.30am to 7pm, and Saturday and Sunday from 8am to 6pm.