The actor passed away of an accidental drug overdose in July, 2013 and Ryan reveals he helped him get into rehab after learning about Cory's addiction issues while working with him on the hit show.

Cory visited the set of Murphy's The Normal Heart with girlfriend and co-star Lea Michele after rehab and indicated he was "getting better" in his battle with addiction. However, the late 31-year-old died soon after and Ryan was left beyond shocked.

"We hugged, and the last thing he said was, 'I love you, man, and thank you for helping me get better', Murphy tells Entertainment Weekly, "and then the next thing I knew he was dead. It was like losing a child."

Following Cory's death, Ryan was instrumental in helping Lea deal with the tragedy and she is grateful she had him to lean on during the difficult time.

"When I found out (Cory had died), Ryan was one of the first people I called," she says. "When Cory was alive, Ryan was very helpful in trying to get him well and healthy but, when that day did come, Ryan did take charge, and he helped me more than I can ever explain."

"He completely cared for me," she continues. "He made sure I was OK every single day, whether it was coming over to his house and having dinner prepared for me, or making sure I was OK at work. He sat me down and said, 'What do you want to do? Do you want to continue the show? Do you want it to end?' I just said, 'I just want to go back to work'. His heart is bigger than I think he knows what to do with sometimes."

However, when the cast and crew returned to the show following Cory's death, the mood of the series had changed.

"What started off as being such a great celebration of love and acceptance ultimately became about darkness and death," Ryan recalls. "It was a great lesson in what not to do moving forward."