Before becoming Austin Powers and Shrek, Canadian comedian-actor Mike Myers performed in an improv duo act with American comedian Neil Mullarkey at the 1985 Edinburgh Fringe. After that, Mike, Neil, and the following act, Paul Merton, collaborated to open London’s Comedy Story Players later that year, and hence, continue on to fame and success.

Source: https://www.distractify.com/p/celebs-discovered-at-fringe-festival