The restaurant has been closed since January while refurbishment works have been carried out.
Diners can still expect to see many of the original features of the restaurant including the wood panelling, harlequin stained glass windows and works by British artists, but with 'contemporary additions'.
On the ground floor the old bar has been removed to open up the space and silver mirrored panels have been added to boost the natural light. A central 'dining bar' mirroring the triangular shape of the restaurant will seat 20 on pink leather and mohair bar stools.
Upstairs, the first floor will host up to 60 guests for private dining events, or 100 for cocktails and canapés.
The menu has also been given a makeover with executive chef Gary Lee including some of The Ivy’s classic dishes along with some new lighter options.
Fernando Peire, director of The Ivy, said: "To survive as long as it has, the restaurant has always had to remain relevant in order to appeal to the next generation. This has been achieved, I would say, through our young workforce, our enduringly appealing yet ever-changing menu and our sheer enthusiasm for what we do.
"Now we have the added bonus of a new interior and a fabulous bar. Some people use The Ivy to celebrate an all-important business deal, special anniversary or event; others for a regular catch-up with friends; some use it as their local canteen and might just pop in for a late bite and a Martini after theatre. We are, I hope, the restaurant for Everyman!"
The Ivy will celebrate its centenary in 2017.
In April, the old contents of The Ivy including the old entrance doors, the ladies’ loo sign and the cloakroom tip tray went under the hammer by Sotheby’s, raising more than £1m for Child Bereavement UK.
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