AceShowbiz - Kevin McHale's "Glee" co-stars did an "intervention" after steroids turned him into a "monster." The 35-year-old actor - who portrayed Artie Abrams on the Fox musical drama series - had been prescribed prenisone in 2011 when he fell "sick as a dog" during a prison time, but the pills had an adverse effect on him, causing Jenna Ushkowitz and the late Naya Rivera to suggest he came off the medication as it was making him "crazy."

"We had just started filming the Super Bowl episode at this time. I think we were filming two episodes at the same time [and] in the middle of it, flying to England. I was sick as a dog on all kinds of medicine including prednisone. It turned me into a monster," he recalled on his and Jenna's podcast "And That's What You REALLY Missed"

But Kevin noted the medication did "give him the courage" to "fight" for his solo in the "Thriller"/"Heads Will Roll" medley performed during a season two episode. However, while on the plain to England and dining with late co-star Cory Monteith, Jenna and Naya called him out.

He said, "You were all like, 'So, hey, why are you taking these steroids?' I'm like, 'Well, because I'm sick, I'm supposed to take them.' You were like … 'I think you should stop taking them.' And I was like, 'Why?!' [You told me] 'You're not sleeping. You're acting crazy. You need to stop taking them.' "

Shocked by what his friends said, the actor immediately agreed to stop the medication. He said, "I hadn't slept in days. I was losing my mind. It was a hard lesson to learn." But Jenna - who portrayed Tina Cohen-Chang on the show - acknowledged that initially Kevin's steroid prescription was "needed" and "necessary" to help him get over his illness at first.