According to new reports, Cory Monteith hid his deadly drug addiction even from those closest to him.

Cory Monteith’s ex-girlfriend, Mallory Matoush, told Us Weekly, that the Glee star was “just a happy guy” and that she saw no sign of the addiction that would ultimately claim his life.

“Cory kept me in the dark about his drug use,” Mallory Matoush told the magazine.

Cory Monteith’s ex-girlfriend Mallory Matoush says the Glee star was “just a happy guy” and that she saw no sign of the addiction that would ultimately claim his life

“He told me about his teenage days and his past problems but he never used anything in front of me, ever.”

“He was always so silly and funny,” she added, explaining that she only ever saw him drink and then never to excess.

Cory Monteith and Mallory Matoush met June 2011 and dated for eight or nine months.

“Cory was so normal. I didn’t even know who he was when I met him,” she recalled.

Mallory Matoush added: “I had to Google it because after the first night I stayed with him, I was on my way out of his hotel and there was a crowd of young girls waiting for him. They asked me if I had seen Cory Monteith inside the hotel and I was so confused.”

Cory Monteith was found on Saturday in his hotel room at the Fairmont Pacific Rim hotel in Vancouver.

The Canadian actor – who completed a stint of rehab in April for substance addiction – was last pictured with his girlfriend Lea Michele just last month.

The news was confirmed by Vancouver Police at a press conference on Saturday night.

It’s been confirmed that Cory Monteith died from a “mixed drug toxicity, involving heroin and alcohol”.

Cory Monteith had checked into the hotel on July 6 and had been due to check out on Saturday.

However, video footage had shown Cory Monteith returning to his room by himself after an evening out with friends on Friday.