Colfer got candid about his relationship with Rivera while talking to E!'s show Daily Pop. "A lot of people probably don't know this, but Naya had the most incredible impressions," the 30-year-old shared. "She was always, always ready to give you one if you were in a bad mood."
"She had this one of Kim Kardashian on jury duty," he said, adding that it would "always make me belly laugh whenever I needed one."
Colfer and Rivera got close while filming the musical series — Colfer played Kurt Hummel, while Rivera portrayed Santana Lopez.
The two were seen holding hands while going through this difficult time.
Nickayla even wrote a heartfelt letter after the death of her sister.
"Sister, there are no words to describe my love for you," she gushed. "Side by side or miles apart, our connection is infinite. Our bond is unbreakable."
"We were complete opposites, yet simultaneously the same. The yin to my yang. I never knew that by losing you, I would find so much of you in myself," she added. "I've never known a life without you in it & still can't imagine it. My world is turned upside down. But through it all, everything we were, we are still."
"I'll always look at you with the same eyes as I did when I was young. My shmaya, I'll love you for eternity & miss you every second of my life," she concluded.
Rivera was confirmed dead on July 13 — five days after she disappeared during a trip to Lake Piru in Southern California. She was reported missing after renting a pontoon boat with her 4-year-old son, Josey.