Frederick Colin Petersen began his acting career at the age of seven. When he was still nine years old in late 1955, he starred in the film Smiley (released in 1956), with Ralph Richardson, but by the time he was twelve in 1958 he was forced to cease acting as his mother felt it was interfering with his education. Other film credits included The Scamp (1957), A Cry from the Streets (1958) and, much later, Barney (1976). In 1958, before his mother took him back to Australia, he was screen tested for the part of the young hero in Tiger Bay, but the part eventually went to the then 12 years old Hayley Mills instead, the part being rewritten for a girl. He attended the Humpybong State School at the same time that Barry, Robin, and Maurice Gibb did (they went to Scarborough State School first, and then later went to Humpybong). Petersen was in Barry's class, though they seldom crossed paths in any significant way. While at school he developed an interest in music, starting out on piano but switching to drums. After leaving school he played with several bands including Steve and the Board, and became acquainted with Maurice Gibb, who invited him to sit in on one of the trio's sessions in Sydney. He ended up becoming friends with the family and ultimately played on as many as a dozen of the Bee Gees' early Australian sides.