Heather Morris is "surprised" by how much she is still "hurt" by Naya Rivera's death

Alongside a black-and-white snap of them cuddling together, she wrote on Instagram: "I can't believe it's been 4 years..boy how time flies. Yet every year I'm taken by surprise how much it still hurts.

"We grow up together, fell apart, and came back together in such a beautiful way. God you're missed so much...except I can't shake the feeling you never left...you're still here with us..guiding us to our highest potential.

"I miss you Nay Nay"

Naya is survived by her husband Ryan Dorsey, 40, and their eight-year-old son Josey, who had been on the boating excursion on Lake Piru near their home in California when the incident occurred.

Naya and her son had briefly swam in the lake but due to the high-speed winds, she insisted they get back on the boat and although she managed to get him back to safety, she did not have the energy to save herself.

In May, Ryan revealed how he and his son were marking Mother's Day in memory of Naya.

Ryan- who was married to the actress between 2014 and 2018 - told E! News: "When Josey was little he loved butterflies and going to the butterfly garden at the Natural History Museum in Los Angeles. "Last year we released a bunch of butterflies while FaceTiming grandma in honour of Naya. He released them and said 'Happy Mother's Day in heaven, mommy!' "It was equally so heart breaking and sweet." Naya passed away almost four years ago, but Jack still finds it to be "surreal". Looking forward to Mother's Day, Ryan said: "We plan to [release the butterflies] again this year. Make it a tradition."