While Caitlyn's luscious locks may be a stylist's dream to work with, her shoe size presents more of a challenge.
"She is so proportionate and yes a size 13 shoe, difficult to find," Diehl admitted. "But I think maybe we'll get lucky now and the Paul Andrew and Tabitha Simmons of the world and Manolo Blahnik will suddenly start making size 13s -- you never know."
Caitlyn's life as a transgender woman will be seen in I Am Cait, E!'s eight-part, on-hour documentary series. The first promo was released on Wednesday.
I Am Cait premieres Sunday, July 26, at 9 p.m. ET/PT. Watch the promo below.