In an interview with the Associated Press at the GLAAD Media Awards on Saturday, Soloway said getting Jenner to join was a "dream come true."
"We are all part of the same community. A lot of the transwomen who work on our show are also in her show, I Am Cait."
Amazon has not officially confirmed Jenner's casting yet.
One of I Am Cait's cast members, Zackary Drucker, is also a producer on comedy show Transparent. Filming begins next week.
The story revolves around a Los Angeles family and their lives after they discover their father Mort (Jeffrey Tambor) is transgender.
I Am Cait is a documentary series on the entertainment channel E!, which chronicles the life of Jenner following her gender transition.
Jenner previously starred with her family in Keeping Up with the Kardashians.
Before her transition, she won the decathlon at the Olympic Games in Montreal in 1976 as Bruce Jenner. She is seen as the highest-profile American to come out as transgender.
In a fan question and answer session on her blog last year, Jenner was asked what had given her the courage to come out.
She says: "I had all of my diversions, sports… this… that… married… family.
"But after 65 years, here I was right back with the same problems that I had when I was 10-years-old and I had to finally do something about that.
"It's been both eye-opening and difficult to see first-hand what so many members of the transgender community have had to go through just to be themselves."
Caitlyn Jenner will appear in the third series of Amazon's Transparent, the show's creator Jill Soloway has announced.