RHS Ambassadors Alan Titchmarsh and Mary Berry will speak at the launch at M&G HQ in London.
RHS director general Sue Biggs will speak about the highlights of the show.
Ann Marie Powell is expected to reveal a Greening Grey Britain exhibit, which will be exhibited in the show feature space at Chelsea, alongside a new green oak RHS shop/info stand on main avenue.
Jo Thompson, Chihori Shibayama & Tea Yano and Philip Johnson with a WW1 ANZAC poppy show feature are set to be in a new space near the hospital, where trees have been cleared.
McVicar made a plea for sponsors through HortWeek in November after her original medical sponsor dropped out. St John’s Hospice is new sponsor.
McVicar won the Lawrence medal in 2009 and has won more than 60 RHS gold medals in all with her business, Jekka's Herb Farm.
Her 2016 garden will be the first herb design at Chelsea for more than 20 years.
McVicar said: "I'm not seen as a garden designer but I'm a bloody good herb garden designer."
She is growing all but 10 of the plants herself for the garden, which is about the power of plants and came about after a lunch with a doctor who has s herb garden and prescribes gardening as a treatment. Talking to him gave a good illustration of herbs very current research proving to be beneficial to man. This is about fact. It's about the bigger picture."