Lea Michele Remembers Late Ex-Boyfriend Cory Monteith on 4-Year Anniversary of His Death: 'Love You More'

Monteith passed away at the age of 31 from a "mixed drug toxicity" of heroin and alcohol

Photo: Source: Lea Michele/Twitter

It’s been four years since Lea Michele said goodbye to Cory Monteith, but her love for him lives on.

In memory of her late ex-boyfriend and Glee costar, Michele posted a throwback, black-and-white photo of the former couple from happier times on Twitter Thursday.

“Hard to believe it’s been 4 years…” Michele, 30, captioned the photo, shared on the four-year anniversary of his death.

“We miss you C… love you more,” she added with a solo red heart emoji.

Monteith passed away at the age of 31 on July 13, 2013; his body was found in a Vancouver, Canada, hotel room. According to authorities, he died of a “mixed drug toxicity” of heroin and alcohol.

The Canadian native completed a month-long stint in a treatment facility for substance addiction in April 2013 and had been open about his lifelong struggles with substance abuse.

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Michele was 26 at the time of Monteith’s passing, and dated the actor for more than a year.

Although the pair hadn’t been photographed together in the recent days leading up to his death, a source close to the actress told PEOPLE at the time, “They were happy and very in love.”

“I love working with Cory, I always have,” Michele told PEOPLE in September 2012. “He really, really inspires me, and he motivates me and I think he’s just so talented. Working with him has been one of the best experiences of this whole process.”