While other guests in attendance at the lavish nuptials on May 24 opted for more conventional black-tie garb, Jenner said Will Smith's 15-year-old son's outfit added "humor to the night", reported Us magazine.
"He is the greatest kid in the world. I'm very close to Jaden and he's like one of my own, you know. He had this Batman costume on and I thought it was just genius.
"When you look at it... It sounds just crazy. (But) it was beautiful. He looked so good, and so fun, and he also has a really good sense of humor," she said.
Jaden's ensemble also came in handy the following day as Jenner, 58, borrowed his boots to wear.
"He saved my life the next day. Because I lost my suit and shoes I had gone to Florence in -- I couldn't find my clothes.
I happened to have a pair of jeans and a jacket and shirt to leave in. But I had no shoes, expect my Giuseppe Zanotti shoes that Guiseppe gave us to wear walking down the aisle, but I couldn't wear those home.
"Jaden came walking out of the hotel and I said. 'Jaden, where's your Batman boots'... And I borrowed them! So, Batman saved the day," she added.