Dame Helen Mirren is warning Americans not to be "pillocks" by drinking and driving in an advert for this year's Super Bowl.

The actress, who has twice famously played the Queen, is seen in a what looks like a plush restaurant, apparently about to tuck into a burger and enjoy a cold beer.

She introduces herself as a "notoriously frank and uncensored British lady" and goes on to give a withering description of drink drivers.

"If you drive drunk you, simply put, are a short-sighted, utterly useless, oxygen-wasting human form of pollution, a Darwin-Award deserving, selfish coward," she says in the 60-second advert, referring to the informal "award" bestowed on those who die as a result of their own stupidity.

She continues: "If your brain was donated to science, science would return it."

But then, to the somewhat regal strains of a rising string accompaniment, she changes tack, saying: "The chances are you're a fun solid respectable human being. Don't be a pillock."

It is unclear how familiar Americans are with the British slang term "pillock".

Each year drink driving incidents in the US spike during Super Bowl Sunday, when friends and family gather to watch the US National Football League (NFL) championships.

Companies spend millions of dollars on celebrity adverts for what has become a US tradition, confident that they will reach a wide audience.

The Budweiser advert featuring Dame Helen is teamed with a social media campaign under the hashtag #GiveADamn.