Chris Colfer says ''the process of losing'' Naya Rivera has been ''such a nightmare''.

The 'Glee' alum - who played Kurt Hummel in the musical drama series - has spoken out following the tragic death of his former co-star and friend Naya, after she passed away in a drowning accident at Lake Piru, California, last week at the age of 33.

In an essay for Variety, Chris wrote: ''I'm not sure anyone on Earth could give Naya Rivera the tribute she deserves.

''In fact, the process of losing her has been such a nightmare, I find myself wondering if Naya was even real or if she was just a dream all along. How could a human being be that talented, that hilarious and that beautiful at once? How could one person be responsible for so much joy and be the subject of so many wonderful memories?''

The 30-year-old actor went on to praise Naya's ability as both a singer and an actress, and said she was the kind of friend he could talk to ''about anything''.

He added: ''As a friend, you could talk to her about anything. She was the cool older sister you went to for advice, to blow off steam, or to get the hottest take on the latest gossip. Just being in Naya's presence made you feel protected and regardless of the situation, you knew she'd have your back. She was never afraid to stand up to authority, she always called out mistreatment where she saw it and she always told you the truth - even when it was hard to hear.''

And Chris also said Naya dreamed of becoming a mother whilst working on 'Glee', after police claimed she spent her final moments pushing her four-year-old son Josey back onto their boat to save his life.

He wrote: ''For as long as I've known Naya, the thing she wanted most in life was to be a mother. She spent hours telling us what she was going to name her kids, how she was going to dress them and all the free babysitting she'd bamboozle out of us. When her son Josey was born in 2015, it was like a missing piece of Naya had finally arrived. Their connection was magnetic, their affection was radiant and I've never seen a person look happier than when Naya gushed over her little boy.

''Being a mom was perhaps Naya's greatest talent of all, and as her final moments proved, Naya was an extraordinary mother until the very end.''