Exclusive Clip: Top Chef Guest Judge Alain Ducasse Shocks Finalists With Surprise Visit

For the first time in Top Chef history, the American reality show went international, filming its 20th season in London. In "Top Chef: World All Stars," 16 former finalists and winners of various international editions of the show have come together to cook for celebrity judges Tom Colicchio, Padma Lakshmi, and Gail Simmons and compete for $250,000.

This week's episode, airing on Thursday, June 1, is sure to be full of surprises as the final four touchdown in Paris. There, the contestants will compete in the infamous Wall Challenge. The judges will be joined by an impressive list of diners, including Greg Marchand, Mauro Colagreco, Alexandre Mazzia, Adeline Grattard, Alessandra Del Favero, and Louis-Philippe Vigilant, who will help determine which two chefs make it to the finals. As if that weren't enough pressure, in an exclusive clip sent to Mashed, the competing chefs get a surprise visit from chef Alain Ducasse — and to say they were starstruck is an understatement.

In the exclusive clip from the Paris episode, chef Tom Colicchio announces himself, along with chef Greg Marchand, as they enter a kitchen where the "cheftestants" are hard at work. Because they are working so diligently, they barely lift their heads to notice that a third person has walked in — legendary chef Alain Ducasse. Trying to get the attention of the contestants, Colicchio makes a comment about how the owner of the kitchen — which is on Ducasse's boat — would like them to keep the place clean. Still, only Sara Bradley seems to notice Ducasse's presence — letting out a little gasp.

Along with Colicchio and Marchand, Ducasse walks around to each of the chefs' stations, discussing the dishes they are preparing for the upcoming competition — even tasting some of them and giving pointers. To find out who will be continuing on to the finals, tune into Bravo tonight, Thursday, June, 1 at 9 p.m.

This episode was made possible in part thanks to Delta, the official airline of "Top Chef" and NBCUniversal's official partner for the 2024 Paris Olympics.