• Emma Thompson: 'one of the best scripts I've seen in years'. Picture: Getty
Thompson, who made her name at the Festival with the Cambridge Footlights company nearly 30 years ago, has ploughed her own money into a play which uses verbatim accounts from two women trafficked separately into Britain.
She will be executive producer of Fair Trade, which the tiny Shatterbox Theatre Company will be staging at the Pleasance this August.
The show came about after writers Anna Holbek and Shelley Davenport met Thompson through her work with the human rights campaign group the Helen Bamber Foundation. The show was developed through more than eight months of workshops, interviews and research.
Although Thompson does not appear in the show, she is expected to visit Edinburgh during its run and has agreed for her name to be used in its title.
The actress said: "I'm extremely proud to be involved in this production; it's one of the best scripts I've seen in years.
"Sex trafficking is a hugely important subject, and I believe we need as much art as we can get to help people understand what's going on out there."
Other major shows at the Pleasance this year include a multi-media musical – Reel to Reel, by Broadway Asia – featuring live performances of classic songs with footage from films like Casablanca, Gentlemen Prefer Blondes, South Pacific, Singin' in the Rain and Guys and Dolls.
Russian physical theatre stars Derevo will be bringing a brand new show to the Fringe as part of the Pleasance line-up, which will also see Mel Smith bring a new show featuring West End star Peter Straker to Edinburgh.
Memory Cells, Glasgow writer Louise Welsh's new play, will star National Theatre actress Emily Taafa, while English soul singer Omar LyeFook will star in a new one-man play, Lovesong.
Big name comedians in the Pleasance line-up include American star Emo Phillips, performing for the first time in nine years, LA comedy scene stars "Ronna and Beverley" and We Are Klang star Greg Davies. Returning festival favourites include Reginald D Hunter, Tim Vine, Al Murray, Arthur Smith and David O'Doherty.
As The Scotsman revealed earlier this year, the Pleasance will be expanding from the south side of the city into the west end for the first time.
A spokeswoman said: "The Pleasance has again compiled a programme combining the best theatre, comedy, music and children's shows. This year sees 23 Pleasance venues across three sites. We have two new venues at the courtyard and now the Pleasance at Ghillie Dhu, a 180-seat venue in the west end."