Cannon, who starred with Bynes in "All That", is concerned about the well being of Bynes after she was put in psychiatric hold, reported E! News.
"As of lately I have been hit with an onslaught of questions about someone I consider family, someone I watched grow up, and someone I genuinely feel is one of the most pleasant human beings I have had the pleasure of meeting, Amanda Bynes," Cannon said.
The TV host and actor stated that he used to "brush it off," but after Bynes' was admitted for psychiatric care, he decided to support his former co-star.
"I've seen it happen to many of my friends and colleagues young and old. It goes back to that old saying; 'Too much of anything is bad for anyone.' Whether it's fame, money, sex, drugs, attention. It's all a dangerous addiction," Cannon wrote.
"We all end up alone in that dark hole at some point in our lives and if you don't have a foundation of friends and family to help bring you up and out it makes that journey long and detrimental."