Standing alongside her fellow co-stars on stage at the Teen Choice Awards, Lea tearfully accepted her award for Choice TV Actress in a Comedy.
Lea started her emotional acceptance speech by thanking those who had helped her in "these very difficult weeks." She then dedicated her award to her late boyfriend who played Finn Hudson on the show.
"I wanted to dedicate this award to Cory, and for all of you out there who loved and admired Cory as much as I did," she said. "I promise that with your love, we'll get through this together.
"He was very special to me and to the world, and we were all lucky to witness his incredible talent, his handsome smile and his beautiful, beautiful heart.
"And whether you knew him personally or as Finn Hudson, Cory reached out and he became part of all of our hearts — and that's where he'll stay forever."
The cast of Glee also received an award for Choice TV Comedy and dedicated their win to Cory. They have started filming for the show's fifth season and have planned a special memorial episode to the Canadian actor.
"Although we lost someone that we really love, that you guys love too, we are very fortunate to come back," said co-star Amber Riley.
"Cory was like a brother to us and like a dad, and you know he was always ready to sign an autograph for a fan — he loved you gleeks and he loved his fans. So on behalf of our brother and our classmate, we accept this award," she said.
This is the first on-screen appearance Lea has made since Cory's tragic death. The 26-year-old is gradually stepping back into the public eye, as she had previously kept a low-profile and chose to reach out to her fans through Twitter.
"Thank you all for helping me through this time with your enormous love & support. Cory will forever be in my heart," she wrote, following his sudden death.
Just last week Lea posted a photo of her on the Glee set, in character as Rachel Berry, alongside the caption, "Feels so good to be home."