Ellis, who reached the final of the BBC kitchen contest earlier this summer, will demonstrate his culinary skills when he appears in the cookery theatre at Southport.
He won the North West heat of the Great British Menu in June after being hailed as a ‘real talent’ by Michelin star-holding judge Daniel Clifford.
Liverpool-born Ellis was still a teenager when he had the vision of turning a shed on a caravan site on Anglesey in North Wales into a dining-out destination.
Eight years later, that shed has become award-winning restaurant the Marram Grass.
For his appearance on the Great British Menu, Ellis created a seafood dish made entirely with ingredients sourced within two miles of his restaurant near Newborough on Anglesey.
Ellis will put on two demonstrations in the cookery theatre at Southport at 12pm and 3pm on Saturday 19th August.
He said: “I’ve heard nothing but great things about the Southport Flower Show (here’s His & Hers’ overview of the show) and it is an event that has grown and blossomed.
“I’m delighted to be involved in the 2017 show, it’s my first big show back home in Merseyside. I can’t wait to cross the bridge and head to Southport.”
Also coming back to Southport to share their cookery expertise with visitors this year are show favourites Luis Troyano and Lilibet Connard.
Luis shot to fame with his skillful cake making in the 2014 final of The Great British Bake Off. He will be returning to the cookery theatre this year on Sunday 20th August.
And the star attraction on Thursday 17th August is Lilibet Connard, the driving force behind Southport foodie destination Lilibets of Paris and a regular guest at the show.
Lilibet opened up her specialist French patisserie after returning to her home town from training in Paris at Le Cordon Bleu.
This year the cookery demonstrations will also be moving into the great outdoors for the first time as a BBQ section with grills and wood fired pizza ovens is set up for the show on a garden terrace.
Experts at Harthill Cookery School, which is an accredited Weber Grill Academy, will give visitors tips on how to avoid burning those burgers and sausages this summer as well as providing inspiration for barbecuing all kinds of foods.
And chefs with Valoriani UK will demonstrate their Forni Volariani wood fire pizza ovens, which are installed at thousands of homes and commercial venues across the country including Harrods and The River Café.
There will be interactive demonstrations at the BBQ section on the garden terrace outside the cookery kitchen at 4pm each day during the show.