"They're really really popular in the equestrian world," organiser Angela Parkinson said. "Just the response we've had already has been awesome."
Kelly, a photographer, has written a bestselling book, For the Love of Horses, about the women's work with Kaimanawa horses, and has just released the new Stallion Challenges. She has plans to write about the sisters' US odyssey as well.
Wilson said she has competed in equestrian events in Masterton before, and looks forward to returning to speak about her latest experiences.
In the United States, she said the "people are amazing - absolutely hospitable".
"We were in the Wild West - real cowboy country. The people have really good values."
New Zealand's Kaimanawa Ranges have about 300 wild horses, with numbers kept to that level to protect native vegetation, with annual musters that bring in about 170 horses to be broken in and rehomed - work which the Wilson sisters have been engaged in for years.
In the US, says Wilson, the problem is on a different scale.
"They have about 80,000 wild horses; they muster all the time, and because they have an anti-slaughter policy they get put into government holding lots."
These thousands of mustangs have "quite a negative stereotype", and Wilson said she is pleased to be raising awareness and to "get the horses out of prison-like environments and having a useful life again".
Wilson placed sixth in the Extreme Mustang Makeover, "competing against 38 of America's best horsemen".
The sisters had been going to spend all their time working with the horses at one ranch, but "got really bored and travelled on the road", trekking with their mustangs through the American landscape.
The TV shows had nothing taken out and were "just us, living life" Wilson said.
"We're not reality TV stars and we don't want to be something we're not. They totally got that."
Wilson's best advice to a child starting out in horseriding is to do it for the fun of it.
"It needs to be fun for you and your horse," Wilson said. "When we started out, there was no competitive pressure; we really just did it for the love of the horses."
Tickets for the evening are available from PGG Wrightson stores in Masterton, Carterton, Eketahuna and Martinborough.
