Lea Michele grieving alongside Cory Monteith's family

Cory Monteith's on- and off-screen girlfriend Lea Michele says she is "deeply grateful" for the love and support she has received from family, friends and fans since Cory Monteith 's death.

Lea Michele plays Rachel Berry, Monteith's love interest on the show

Richard Branson talks about working with Cory Monteith 7:06

Cory Monteith's on- and off-screen girlfriend Lea Michele says she is "deeply grateful" for the love and support she has received from family, friends and fans since Cory Monteith 's death.

Monteith, 31, was found dead in his hotel room at the Fairmont Pacific Rim in Vancouver on Saturday. According to the B.C. Coroners Service, the Canadian actor died from a toxic mix of heroin and alcohol.

Monteith was best known for playing Finn Hudson, a football quarterback with two left feet who found more camaraderie in the choir room than on the football field, on the hit TV show Glee.

Since his death, many of Monteith's castmates have reacted publicly, expressed first shock and sadness and later, their condolences via Twitter and other forms of social media.

But Michele, who plays Rachel Berry, Finn's love interest on the show, remained silent until Wednesday, when she released a statement through her representative.

"Since Cory's passing, Lea has been grieving alongside his family and making appropriate arrangements with them," the statement read. "They are supporting each other as they endure this profound loss together. We continue to ask the media to respect the privacy of Lea and Cory's family."

Another castmate, Diana Agron, who played cheerleader Quinn Fabray, also spoke out.

"My heart goes out to his family, to Lea, to everyone that is struggling with the loss of our friend. We will miss you Cory. We will always carry a piece of you with us," the actress said.

"Glee was a gift to all of us. It gave us a family in this industry. We really cut our teeth and grew up on this show. In playing underdogs, we learned that we had dug into the hearts of our viewers and that we could stay there… Cory is so deserving of that place in everyone's hearts."

Richard Branson calls death "a terrible waste"

British billionaire and Virgin Group founder Richard Branson, who worked with Glee’s Cory Monteith on several charity projects, called the young actor’s recent drug-related death "a terrible waste."

"He was an absolutely delightful young man. He cared enormously about other people," Branson told CBC News via Skype from Necker Island, in the British Virgin Islands.

"He’d decided to sort of spend his life trying to help the 65,000 homeless youth in Canada to get off the streets and get a decent life. But he had this demon, which was drugs, and sadly it never went away. But in his short life he achieved an enormous amount, and I think has made a big difference in people’s lives. It’s just a terrible waste."

Before his death, Monteith had been eager to help young people struggling with homelessness and addiction.

Monteith and Branson worked together on Project Limelight, a free performing arts program for kids living in Vancouver’s troubled Downtown Eastside, and Monteith was an ambassador for Branson’s Virgin Unite charity.

"He was tremendous," Branson said.

"He obviously related really well to people. He’d had his own problems, which were very similar to the problems of a lot of youth on the streets, and I think a lot of us thought he’d overcome them. But obviously he hadn’t, sadly, and what we’re hoping is that we can continue his good work in the future and hopefully help avoid other kids having the same problems."

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Branson said he and Monteith spoke generally about drug addiction and drug policy, but never about the actor’s personal struggle with addiction.

"The difficulty is if you are in the public eye, admitting that you’ve got a problem — it’s illegal to take substances in Canada and it’s difficult to go to get help. So I think if there’s a change in mindset, people who have problems will be able to confront them publicly and get help and hopefully avoid the absolute disaster that happened to him," he said.

"Obviously it sends a message: heroin is dangerous, it’s lethally dangerous. And you don’t even know if it’s heroin that you’re taking …. So obviously the message must be to try to avoid it if you can and if you have got a drug problem, forget the fact that it’s illegal — just go and get help and do everything you can to get off it."

Branson says Monteith will be remembered fondly.

"He had a great sense of humour, he was fun, he threw himself into life," he said.

"He didn’t just think about himself with his acting career, but he found time for others, and others absolutely loved and adored him. And he’ll be a very sad loss — but we hope to raise lots of money … in his name."

Monteith’s family and friends have selected three charities — Project Limelight, the Chrysalis Homeless Service and Virgin Unite — to receive donations in his honour.

Despite a large number of overdoses linked to heroin and fentanyl in the Vancouver area in recent months, on Wednesday B.C. Coroners Service spokewoman Barb McLintock reiterated that the toxicology report found no fentanyl in Monteith's system.

"Toxicology results did not indicate any presence of the drug fentanyl," said McLintock.