Hundreds of people have already booked their tickets for the Chorley Council-run event, which will see Gardeners' World presenter Carol Klein and garden designer and television presenter Joe Swift carry out gardening demonstrations and taking part in a question and answer session.
The duo hosted the BBC's coverage of the RHS Chelsea Flower Show last week and were selected by popular demand after the council asked people who they would like to see at this year's show.
Cllr Alistair Bradley, leader of Chorley Council, said: "We're delighted to have two prestigious names from the horticultural world taking part in the show and it will be an opportunity for people to meet them both.
"The celebrities were a big draw last year so we took the opportunity to see who people would like to see when asking for feedback on last year's show. Both Carol and Joe were the most popular suggestions and I'm delighted they're both able to attend the show."
The show will also be an opportunity to see Chorley's new Victorian Glasshouse, which will be growing exotic fruits.