In the sepia image, the actress can be seen staring pensively into the distance as she sits alone on a trunk at the end of a bed.
"Feels so good to be home," the brave star wrote in a caption to accompany the picture, who shows her back in character as Glee's Rachel Berry.
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The evocative image comes as a stark contrast to the last photograph Lea shared with her fans on Twitter. Shortly after Cory's death, she posted a personal picture of herself in the arms of her boyfriend, the couple clearly very happy as they smile for the camera.
"Thank you all for helping me through this time with your enormous love & support. Cory will forever be in my heart," she wrote in the accompanying caption.
Lea and the rest of the Glee cast returned to work last week, less than a month after the tragic death of 31-year-old Cory.
"First day of glee today... And at my first wardrobe fitting for Rachel Berry for Season Five! I've missed her so much," the actress tweeted on 1 August.
On Monday, the dark-haired beauty was spotted leaving a recording studio in Hollywood after recording new material for the fifth season of the hit musical show.
She her fans that the show had chosen the "beautiful & perfect song" for her return, following Cory’s untimely death.
The fifth season of Glee will premiere in the US on 26 September and will air a special memorial episode for Cory on 10 October.