Burger King has invited customers to take a bite out of what may be the first-ever "gay burger" - the Proud Whopper.

The fast food giant beefed up its diversity credentials by reaching out to the LGBTQ community in Gay Pride week.

Branches in the city of San Francisco served up whoppers wrapped in the multi-coloured flag of gay activism.

But anyone expecting something different from the patty was let down because it was no different at all to a standard Whopper burger.

Apparently, this was all part of the plan, as inside the wrapping was the slogan: "we are all the same inside."

The Proud Whoppers will be on sale for just one week.

A Burger King spokesman said: "As a brand, we welcome everyone. We felt the Proud Whopper could bring to life a message of equality, self-expression, authenticity and just being who you are."

The Proud Whopper received a broadly positive reception in the gay press, although some body-conscious critics said it would not constitute a healthy option.