Only a week after Cory Monteith's tragic death, details are slowly surfacing about the actor's last days.

Us Weekly reports that the Monteith's girlfriend, fellow 'Glee' star Lea Michele, knew he was planning a surprise for her upcoming birthday in August.

"She didn't know what," the source said. "But she thought it could be a party and possibly a trip somewhere."

The couple was also preparing to take the next step forward in their relationship -- moving in together!

"Lea and Cory were planning on moving in together after he got back from Vancouver," another insider told Us, adding that Monteith and Michele "weren't talking engagement or marriage yet, but it was heading that way. The first step was [that] Cory was going to move in [to Michele's L.A. home] completely. He was already there all the time."

In an interview with Marie Claire, given before Monteith's death, Michele opened up about her boyfriend.

"But he is the best person I know, he has made my life so incredible, and I am so thankful for him and not only to have him as a partner but also as a co-worker," she said, adding, “It is important to have someone that supports you and encourages you, someone that makes you feel that you are unstoppable, that you can do anything in the world because you have him.”