Determine if the sentence is true based on the text below:
Mark Kounnas was known as Gekko in the movie Mad Max Beyond Thunderdome.

Mark Kounnas (born 1969) is an Australian actor and television presenter. Mark has had many acting roles on television and films and is probably best known for his role in "Mad Max Beyond Thunderdome" as Gekko. He has also been a television presenter on an ABC children's television series with his sister and fellow actor Melissa Kounnas.
Yes