The hunky star captioned the flashback Friday photo from 2008, "So grateful I came across this picture... with the o.g. crew during one of the most cherished times of my life. #fbf"
Efron was recently noticeably absent from a HSM reunion. At the top of the year, Hudgens, Tisdale, Lucas Grabeel, Bleu, and Monique Coleman reunited in a Los Angeles high school gym to celebrate the Disney Channel movie's 10-year anniversary.