The rapper and Rivera were previously engaged between 2013 and 2014, but ultimately went their separate ways.
In an Instagram post on the weekend, Sean shared two photos of Rivera—one of her in black and white and another of her holding her son, Josey Dorsey.
"Rest In Peace Naya, God Bless your Soul!," he captioned the post. "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 [sic] watching over them and protecting them. Rest In Peace Naya 💙🙏🏾."
The post comes after a bit of social media backlash that saw people criticising the rapper for a song he wrote in 2014. The song, called "IDFWU," was widely believed to be about Rivera and people in the rapper's Instagram comments felt the song was now "disrespectful."
That said, the pair apparently had no ill will between them. Rivera even playfully performed the song on Lipsync Battle back in 2018.
Rivera's co-star Heather Morris also shared her own post about her close friend. In two posts, one of the pair of them and the other a series of sweet pictures of their kids playing together, the actress remembered how incredible Rivera was as a person and a friend.
"You constantly taught me lessons about grief, about beauty and poise, about being strong, resilient and about not giving a fuck (but still somehow respectful)," she wrote. "Yet, the utmost important lesson I learned most of all from you was being a consistent and loving friend. You were the first to check in, the first to ask questions, the first to listen... you cherished our friendship and I never took that for granted."
Morris and Rivera played Santana and Brittany, one of Glee's most beloved couple who were trailblazers when it came to queer relationships between women on TV. You can read her touching posts in full below.