Demi Lovato and Heather Morris are among the Glee actors sharing messages of hope and requests for prayer after co-star Naya Rivera went missing at a lake in southern California.

Venture County Sheriff’s Department said it is searching for a “possible drowning victim” after Rivera’s four-year-old son was reportedly found alone on a rented boat at Lake Piru.

Rivera, 33, is best known for playing mean cheerleader Santana Lopez on the musical comedy series.

Morris, who played Santana’s best friend Brittany S Pierce, on the show, wrote on Instagram: “We need all the prayers we can get to bring our Naya back home to us. We need your love and light.”

Harry Shum Jr, who played fellow student Mike Chang tweeted: “Praying.”

Meanwhile, singer Lovato, who played waitress Dani in the fifth series of the show, shared a photo of a burning candle and wrote: “Please pray for @nayarivera to be found safe and sound.”

According to local reports quoting the sheriff’s department, Rivera rented a boat at Lake Piru at about 1pm local time on Wednesday.

The alarm was raised and a search operation launched using helicopters, drones and dive teams.

On Tuesday, Rivera tweeted a picture with her son, captioned: “Just the two of us.”

The actress earned significant success starring as high school cheerleader Santana in Glee and the California-born star followed it up with her feature film debut in 2014 horror film At The Devil’s Door.

She later had a role in the Lifetime TV series Devious Maids.

Rivera became engaged to rapper Big Sean in October 2013 but they ended their relationship in April 2014.

She then began dating actor Ryan Dorsey and they married in Mexico in July that year.

The couple had son Josey Hollis in September 2015. Rivera filed for divorce after two years of marriage but they later called off the separation before finalising their divorce in June 2018.