Electra Partners has agreed the acquisition of the UK franchise of TGI Fridays in a deal thought to be worth £225m.
It has invested £100m of equity in the deal for the company alongside its management team, led by chief executive Karen Forrester (pictured).
The American-themed casual dining chain has 66 restaurants in the UK.
Forrester said: "In Electra Partners we are delighted to have found a long-term partner capable of supporting our growth ambitions, as we look to further expand TGI Fridays' share of the UK market.
"TGI Fridays' best-in-class service, unique bars and exciting dining environments create a unique guest experience with a wide demographic appeal. The enthusiasm of our team members is the key to this and they will remain at the centre of our offering."
Bill Priestley, partner at Electra Partners, added: "TGI Fridays is exactly what we look for in an investment - an attractive, differentiated business with an impressive financial track record and an excellent management team. We look forward to working with Karen Forrester and her team to develop the business further through a mixture of organic growth and new restaurant openings, while at the same time continuing to improve the existing sites."
TGI's owners, Sentinel Capital and TriArtisan Partners, bought the company, which has more than 900 sites around the world, for $880m (£564m) earlier this year. It appointed Rothschild to oversee the sale of its UK arm in the summer.
In October TGI Friday's opened a new site at the Silverburn shopping centre in Glasgow and said it expected to open around 120 new sites in the UK by 2020.