It has been one full year since the tragic and sudden death of Corey Monteith.

On Sunday (July 13th), the 1-year anniversary of the actor's passing, several 'Glee' cast members took to social media to pay tribute to him.

Monteith, who played Finn Hudson in the comedy/musical TV series, was found dead at noon on Saturday 13th July 2013, when he was staying at the Fairmont Pacific Rim Hotel in Vancouver.

The corner lists the 31 year-old's official cause of death as "mixed drug toxicity, involving intravenous heroin use combined with the ingestion of alcohol."

Lea Michele, who was his real-life girlfriend, shared a cute photograph of the pair on Instagram, which showed herself and Monteith posing together on a beach, with a love heart as the caption.

The 27 year-old, who plays Rachel Berry on the FOX series, also posted another pic of the late actor on Twitter, accompanied by a heartfelt message.

"We hold you in our hearts today, and every day we remember your smile. We will love you and miss you always," she wrote.

Other original 'Glee' stars, including Matthew Morrison, Amber Riley, Jenna Ushkowitz and show creator Ryan Murphy, also joined in on the tributes on Sunday.

Riley, who portrays Mercedes Jones, tweeted, "I remember your smile and your warm hugs! 1 year without you and your presence is still felt. Miss and love u everyday big bro. Our Angel."

"I personally believe Cory was reborn into some other beautiful form a year ago today," added Morrison. "I celebrate him and his life... Wherever that may be."

More: On Cory Monteith's 32nd Birthday, Lea Michele Pays Tribute To Her Late Partner

"365 days since you've gone and not a day passes we don't remember your smiling face," Jenna Ushkowitz wrote on Instagram after uploading a rare photo of several 'Glee' actors with Monteith during a scene. "We miss you buddy. Thanks to everyone for your love and support today while we remember our quarterback."

More: Cory Monteith's Father Is Still Mourning The Actor, But Thinks Lea Michele Should Move On

These tributes also caused the hashtags #1YearWithoutCory and #RememberingCory to trend on Twitter.