Yes, that’s Stevie Starr aka ‘The Regurgitator’, a staple of the '90s cabaret circuit.
Some of his act relies on him having swallowed stuff before coming on stage- for example, he swallows a miniature scrambled Rubiks cube and regurgitates it solved. The powdered sweetener that he brings up is probably held in a sachet in his mouth that he breaks open at the required moment. But this is not in any way to belittle his undoubted, and unique, talents.