Sandusky has been indicted on 40 counts of sex crimes against young boys following a three-year investigation sparked by allegations the Penn State coach had had inappropriate contact with a 15-year-old boy over the course of four years.
Eight boys have since been identified as victims of sexual advances or sexual assaults by Sandusky.
The scandal has rocked the U.S. sports world and Perry has heaped praise on the boy who kickstarted the investigation by coming forward.
In his letter, printed in Newsweek magazine, the Madea Goes to Jail director and star writes, "What you have done is so courageous. The strength that it must have taken for your 11-year-old voice to speak out about such a horrible act is something that I didn't have the strength or courage to do at that age."
Perry opened up about his own sexual abuse as a child in 2009 following the release of Precious.
He added, "I knew what was happening to me, but unlike you, I couldn't speak about it because no one saw me. I was invisible and my voice was inaudible. So to think that you, when you were only 11 years old, spoke up - you are my hero! I'm so proud of you."
He is now urging the unnamed teenager to testify against Sandusky in court: "You may have to go through with that trial, and you may feel all alone when you're on that witness stand, but just know that there are millions of young boys and grown men who are standing with you - including me."