United Kingdom, Jan. 10 -- Isaac Mizrahi declares Gwyneth Paltrow "has the best a** in show business".

The 64-year-old fashion designer used to create clothes for the 53-year-old actress in the 1990s, and he reunited with the star in Marty Supreme, in which Isaac played her alter ego Kay Stone's publicist, Merle.

Isaac told People: "I used to make clothes for Gwyneth in the '90s. I swear to you, I remember when she used to come in for fittings.

"She would leave after things, and I'd say that girl has the most fabulous ass I've ever seen. She has the best ass in show business, I mean that.

"That's the one thing I can remember about Gwyneth. Except for the fact that she's hilarious and so good in this."

The 1950s-set ping-pong drama Ma...