ShowbizSpy.com reports that Lea is, as you'd expect, "devastated" by Cory's passing.
According to the website, Lea found out about Cory's death by telephone, with a source explaining, "Lea broke down in tears when she heard the news. Cory was her whole world. They've been through a lot together."
Lea had stood by Cory's side when he went to rehab this year, releasing a statement at the time that read: "I love and support Cory and will stand by him through this. I am grateful and proud he made this decision."
Lea's recent tweets have included bikini and vacation pics, a flashback of when she gave Beyonce a Grammy, and a reminder for fans to vote for her for the Teen Choice Awards.
Fans on Twitter sent out their condolences to Lea, with rumors flying that she and Cory were expected to get married soon.
Fans have been using the hashtags #RipCoryMonteith, #StayStrongLea and #prayforlea to express their sadness.
Gallery | R.I.P. Cory Monteith