And the actress has been heartened to learn that many fans are standing by them as well.
The 26-year-old Glee star took to Twitter Tuesday to thank her followers for their outpouring of support.
"Still so overwhelmed by all the love and well wishes we have received from you all..my heart is so full," she wrote.
Monteith, who voluntarily checked into rehab last week, has been open about his past struggles with drug addiction, telling Parade magazine in 2011, "I'm lucky to be alive."
The 30-year-old actor's Glee posse has also rallied behind him.
"Cory is a beloved member of the Glee family and we fully support his decision to seek treatment," a show rep said in a statement. "Everyone at the show wishes him well and looks forward to his return."
Michele, for one, is keeping a positive outlook amid the trying circumstances. "It's such a gorgeous day out today," she tweeted. "I hope everyone has a beautiful day."
It's a sentiment, no doubt, echoed by many fans, who hope that Michele and Monteith will soon be able to look forward to sunnier days together.