Actor Robert De Niro has lent his support to a 100,000 US dollar (£80,250) offer to journalists who publicise criticism of vaccination in the US.

He sat on a panel of speakers led by Bobby Kennedy Jr, who urged the media to scrutinise the use of thimerosal, which contains mercury, in children’s vaccines.

The Dirty Grandpa star said few words at the event, but backed Bobby’s proposal to “offer 100,000 dollars to start talking about this issue honestly”.

Robert, 73, said: “I thought what Bobby said was great.

“It was eloquent. I couldn’t have said it better myself. I agree with him 100%.”

During the conference, Bobby linked thimerosal to the development of autism in children.

But according to the Minnesota Department of Health, studies show “no association” between the two.

Robert, whose son has autism, said that it would be a positive step if Donald Trump were to support Bobby’s team.

While he has publicly criticised the US president, he said: “Trump I don’t care about, if he does the right thing he does the right thing, I don’t have to be connected to him”.

But listeners have attacked the actor on Twitter for getting involved in the campaign, with many labelling it as “nonsense”.

I wish I couldn't read because I just found out Robert De Niro is a public anti-vaccine supporter and I've lost all respect for my fav actor

— Casey Bergeron (@BergCasserole) February 17, 2017

Others have ridiculed the cash offer, suggesting that Bobby and his team hold the responsibility to prove that vaccinations are harmful.

Are Robert De Niro and RFKjr serious about this #vaccine thing? Cuz...I already have proof they work, and I could really use 100k right now

— 🇨🇦ProudBoysNorth (@ProudBoysCanada) February 17, 2017

Bobby hit back at reports accusing him of being “anti-vaccine”, insisting that he just wants a “safe vaccine”.

“That word ‘anti-vax’ is a dirty word used to shut down debate,” he said.

“Journalists need to stop doing that and they need people to stop talking about it.”