B+K started work this week at the site where it originally built Fosse Park almost 30 years ago.
The Crown Estate has also awarded a £4.9m deal to Faircloth Construction to modernise store facades at the centre and deliver improvements in the car park and surrounding public realm.
Construction work is due to be completed in 2020.
Gary Bradley, Regional Director, Bowmer + Kirkland, said: “Some of our staff who worked on the original scheme 30 years ago are still with us and it’s great for them to see how the development is growing.
“We are looking forward to working with all our partners to deliver this scheme.”
Darren Faircloth, Director, Faircloth Construction, said: “We are delighted to be continuing our work with The Crown Estate to modernise the look and feel of the current development.”