Singer Demi Lovato has come under fire from fans for sharing a video of her mother joking about the Zika virus.

Demi Lovato

The 23-year-old shared a clip of her mother Dianna Hart, who could be seen drinking alcohol, on her Snapchat story, in which she said: "Everybody down in Rio gonna get the Zika virus".

Lovato could be heard laughing in the background and added three laughing emojis to the video.

Fans made #DemiLovatoIsOverParty trend on Twitter as they hit out at her mother for making the insensitive comment about the virus, which causes birth defects in babies and has badly affected South America, including in Olympic host country Brazil.

The hashtag replicated the one Taylor Swift received after her fall from grace following a video of a conversation between her and Kanye West in which she gave him permission to use her name in his song Famous going public.

One young fan named Duda fumed on Twitter: "Zika virus is not a joke."

Another wrote: "That is just rude. Does Demi not know that the Zika virus affects women and babies development. How is the Zika virus something that should be made fun of like laughing at people who have diseases such as diabetes."

A third added: "Zika isn't a joke exactly like mental diseases aren't. Your fans are disappointed."

A fan named Dalia asked why Lovato had shared the video. "I understand that it was her mother who made the joke & Demi laughed at her, but why post the video in the first place?" she asked.

However, some defended the Skyscraper singer, pointing out it was her mother that made the crass joke.

One wrote: "Demi's mom is the one who said it. She was noticeably drunk. You can't blame Demi for someone else's actions."

Another weary fan wrote: "You can't blame demi for something she didn't do. she didn't make the joke, it was her mum. y'all are so pathetic."

A furious fan accused those attacking Lovato of being hypocrites about the Ebola outbreak in 2014. @marylin_gu wrote: "It was her damn mother!! Being drunk may not be an excuse, but y'all were joking about Ebola while sober. Get a life."

Lovato has yet to make a response.