Johnson has teamed up with the creators of the 5000 Poppies Project to create the display, which will honour all servicemen and women who have fought across all wars, conflicts and peacekeeping operations over the last 100 years.
The show feature has drawn comparisons to the ceramic poppy installation at the Tower of London in 2014. It will incorporate a selection of poppies from 50,000 contributors from across the globe.
The design by Johnson features a simple central geometric installation, complemented by more than 25,000 stemmed poppies covering almost 2000sqm.
The project came from humble beginnings, when in 2013, Australians Lynn Berry and Margaret Knight set out to crochet 120 poppies to plant at the Shrine of Remembrance in Melbourne, in honour of their fathers who both fought in WWII. However a huge outpouring of community spirit and creative energy saw the project quickly snowball.
By Remembrance Day 2013 more than 5,000 poppies had been collected, and by Anzac Day 2015 the total was more than 250,000 poppies from contributors around the globe. They were "planted" in Melbourne's Federation Square and on Princes Bridge, and led to an invitation to showcase at the Chelsea Flower Show.
The design will extend into the lawns of the Chelsea Hospital, which has been opened up to the showground through the felling of 30 trees. That move was part of a landscaping scheme in line with Sir Christopher Wren's original vision for the site and has also made space for two additional show gardens at Chelsea.
This is the first time that the RHS Chelsea Flower Show has connected into the grounds of the hospital in such a dramatic way. Chelsea organisers expect the installation to be a highlight at the show.