Moss laughed as Kimmel played the 1990s-era clip of her contorting her legs so that her feet touched her face, while she sat on a table.
"It's so weird," Moss said as she looked at the video monitor.
A dog then ran on stage in the footage, ripped the cloth off the table and revealed Moss was using false legs to create the illusion. Moss then hurried off with the table as the audience clapped.
"Oh, my goodness! It was a trick. Those legs looked so natural," Kimmel teased. "Whose idea was it to have a 9-year-old girl put her legs behind her head on television?"
"Also, it was Circus of the Stars, but I wasn't famous. I was 9 years old. No one knew who I was," Moss said, adding that she had never seen the video before.
Moss, who was a cast member of Picket Fences when she appeared on Circus, also revealed she is not an adventurous person and wasn't interested in performing on a trapeze or participating in any other risky Circus stunts, so the contortionist act was all they could get her to do.
"I don't even like hiking. That is too much for me," she said.
Moss, 37, was on Live! to talk about her projects The Invisible Man, The Handmaid's Tale and The Kitchen.