Big Sean has paid an emotional tribute to Naya Rivera.

The 33-year-old actress drowned in Lake Piru, California, earlier this month after helping her four-year-old son Josey to safety and her former fiance Big Sean, 32 - who was engaged to Naya in 2013 - admitted he is ''still grieving and in shock''.

He wrote on Instagram: ''Rest In Peace Naya, God Bless your Soul! Thank you for blessing us all with your talent and presence. you are a hero! Not just because of how you saved your son, also because of the barriers you knocked down for so many people to make them feel confident in themselves and to stand tall and be proud when they couldn't achieve that on their own. I appreciate and cherish everything that ever happened between us for making me wiser and a better person. I'm still grieving and in shock, I can't believe this is real. I'm praying for you and your family and I know your watching over them and protecting them. Rest In Peace Naya (sic).''

Naya had rented a boat for a day on the lake with her son, it is believed that she got into difficulties while swimming and managed to get Josey back on the boat but was unable to save herself.

Josey was found asleep in the rented vessel by another boater and later told Ventura County Sherriff's deputies that his mother had gone swimming in the water, but didn't get back up.

The Ventura County Medical Examiner's Office has confirmed that Naya's cause of death was drowning.

The Medical Examiner's Office said in a statement: ''The circumstances and visual characteristics all indicated that the body was that of Naya Rivera and the identity has been confirmed by dental comparison. The autopsy findings are consistent with a drowning and the condition of the body is consistent with the time that she was submerged. No traumatic injuries or disease processes were identified at autopsy.''