A body has been found at the California lake where former Glee actress Naya Rivera went missing, police have said.

The 33-year-old disappeared while on a boating trip with her four-year-old son at Lake Piru on Wednesday.

A rescue mission was launched but less than 24 hours later police said Rivera, best known for playing a high school cheerleader on musical comedy series Glee, was presumed dead.

A body was found on Monday, Ventura County Sheriff’s Office said.

Recovery is in progress and a news conference will take place later.

Rivera is feared to have drowned at Lake Piru, which is a popular spot for swimmers about 56 miles north-west of central Los Angeles.

Her son, Josey Hollis, was found asleep and wearing a life jacket on the boat, with his mother nowhere to be seen.

He told police he had seen her disappear beneath the surface.

CCTV from the dock shows her rented boat departing at about 1pm and it was later found drifting in the northern area of the lake at around 4pm.

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Actress Naya Rivera went missing after taking this rented boat out on Lake Piru in Southern California (AP Photo/Chris Pizzello)

Investigators had stressed the many difficulties posed by the search, including strong currents, dangerous underwater debris and visibility of 1ft-2ft.

On Sunday, police extended their search to the cabins and outbuildings around the lake – as well as taking another look at the shoreline.

It came after an online petition demanded the search be extended in case Rivera had left the lake.

Police said they were almost certain she was still in the water. Sonar had been used to scan the bottom of the lake while police divers and cadaver dogs also took part in the search.

Rivera looks increasingly likely to become the third major cast member from Glee to die in their 30s.

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A rescue mission was launched after former Glee actress Naya Rivera went missing at Lake Piru and a body has been found (AP Photo/Ringo H.W. Chiu)

Co-star Mark Salling, who Rivera dated at one point, killed himself in 2018 at age 35 after pleading guilty to child pornography charges.

Cory Monteith, one of the show’s leads, died at 31 in 2013 from a toxic mix of alcohol and heroin.

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 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.