The 33-year-old actress disappeared on 8 July while out boating with her four-year-old son Joey at Lake Piru, and though authorities have admitted she is likely to have drowned, her former 'Glee' co-star insisted all is not lost.
Kevin tweeted: ''I cannot begin to understand what Naya's family must be feeling. I know the rest of us are completely shattered, but not without hope. Please respect her family & their privacy in this moment. Please refrain from judging those who don't show their pain on social media.''
Kevin wasn't the only star to urge fans not to put pressure on Naya's friends to comment on her disappearance online.
Amber Riley asked her Twitter followers to ''show some respect'' amid the ''devastating'' situation.
She posted: ''Show some respect. All our energy is going toward helping find Naya and praying for her safe return and for her family,.
''No one owes anyone online a performance of grief. This is very real and devastating. Focus on Naya and her family. Not us. We don't matter right now.''
And director and choreographer Adam Shankman hit out at people wanting to see ''grief theatre''.
He wrote on Instagram: ''At this time there is nothing to be said about Naya other then we are praying for her and her family and a miracle.
''There is no space for grief theater right now. But prayer and hope are more than welcome.''
Meanwhile, the Ventura County Sherriff's Office have warned anyone ''intent on searching for Naya Rivera on your own'' not to do so because conditions are very dangerous.
They explained on Twitter: ''1. The lake is closed. 2. Temps are already in the 90's. 3. The terrain around the lake is very steep and rugged. Our teams are well equipped and highly trained. We don't want to have to rescue you.''
Josey - who is safe in the care of his father, Naya's ex-husband Ryan Dorsey - had been found along on the rented boat and told authorities his mother hadn't got back in the vessel after going swimming.
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