The chef has been appointed chef consultant by the group, which has held the contract to supply catering at The National Museum, Cardiff, St Fagan's National History Museum and the National Waterfront Museum, in Swansea since 2006, and will work alongside its development chef Leon Williams to create a series of menus for weddings and corporate events at the museums.
Hill, who re-opened The Walnut Tree in Abergavenny with Caradog Hotels in 2007, will focus on using quality Welsh produce as the basis for menus and will also give training to Elior staff in his own restaurant's kitchens to ensure menus are delivered to Michelin-starred quality.
“It is up to everyone involved in catering in Wales to step up and raise the bar and level of expectation, which makes being involved in the creation of these special menus for events and weddings at the three museums an exciting prospect," he said.
“With an eye on using great ingredients presented in the very best of ways, my aim is to create a range of menus fitting of the venues and the special events that they will be produced at.”
Elior, who won a 10 year contract extension worth £28m last week to provide catering at the three sites, will also invest £84k in its catering operation at St Fagan's.
David Carr, commercial director, Elior UK, said: “The investment will include two new restaurants and a number of catering concepts around the site including converted trams serving hog roasts and barbecues featuring pork from pigs reared at St Fagans. Coffee from locally roasted beans and Welsh cakes will also be added to the menu to increase sales throughout the year."
Plans also include the conversion of a pottery shed at the open air museum into a Welsh tea room to be used while the refurbishment of existing facilities is in progress.
Commenting on the partnership, Phil Smith, chief executive of Enterprises Ltd, National Museum Wales said: “It’s fantastic to be working with a company that is familiar with our brand, the day-to-day running of the museum and what we try to achieve as an organisation.
“Elior consistently offers not only high quality produce but also sources local produce that reflects Wales as a nation. Our visitors expect a taste of Wales; and an excellent one at that. Offering local produce completes the Welsh experience for our visitors.”