The restaurant, which opened in 1991, is closed until April while work is carried out to refurbish its dining rooms and Martini Bar and create a new Club Room for private events.
Head chef Francis Agyepong will also spend some time overhauling the menu that will include new American dishes alongside Christopher's classics 'to prove that American cuisine goes way beyond steaks and burgers'.
Christopher's director Anika Paul, whose father Ambar bought the restaurant in 2010, said with the current revived interest in American food, it was the right time to give the restaurant a new focus, with plans to open it as an all-day operation, serve brunch at the weekends and host more private events alongside the new Art Deco look.
She said: "Christopher's has been a part of the Covent Garden restaurant scene for over 20 years - it was the original American restaurant in London, doing steaks, burgers and shellfish well before today's trend and in doing so acclaimed a great reputation as one of London’s best in American cuisine.
"Since we bought Christopher’s in June 2010, I’ve spent over two years working at the restaurant, talking to our regulars, and understanding our strengths. We felt it was now time to give a new lease of life to the building, but retaining the essence of what makes Christopher’s so popular."
Covent Garden
Having operated in Covent Garden for more than 20 years, Christopher's has been a stalwart in an area that has seen a host of high profile restaurant openings in the last two years, such as The Delaunay, Jamie Oliver's second Union Jacks, Meat Market, Balthazar and the soon-to-open Shake Shack from Danny Myer.
Paul said despite the increasing competition in the area, Christopher's had won a 'great reputation' as one of London's best in American cuisine so had not felt the impact. In fact, she said the new openings had benefited the business.
"I think Christopher's success lies in the fact that its focus has always been on the customers and the kitchen produces good food that everyone wants to eat, seemingly more so now than ever before," she said.
"It’s wonderful to see so many great restaurant names opening up in Covent Garden, and our area is finally being recognised as one of London’s best destinations for eating out. We’ve seen an enormous influx of people in Covent Garden, and last December was Christopher’s busiest ever."