As we know, one way activists like to energize a serious campaign is to make them fun. That’s the approach taken by a group of young UK campaigners who want to shine a light on the lack of on-screen diversity.

In what one local communications director described as the PR stunt of the day, a group of young black Londoners going under the banner Legally Black, have reimagined the posters of famous movies and TV shows such as Titanic, Harry Potter and Doctor Who by replacing white actors with black leads. “If you are surprised it means you don’t see enough black people in major roles,” says the group, many of whom are teenagers. Legally Black chose a fitting week to go viral as movies and activism will be particularly linked this weekend. Something tells me Three Billboards’ Mildred would approve.

Related Story Annual Survey Of Film Critics Finds Persistent Gender Disparities, Profound Impacts

The group, which roped in friends and family to star as their new ‘actor leads’, initially reached out to private media agencies about an official campaign on London buses but didn’t get a response. So fellow activist unit Special Patrol Group, which has in the past run “vandal advertising” campaigns targeting police corruption, took it on themselves to print out the posters and placed them in bus stop billboards overnight this week.

The stealth campaign, which has been seen in the Brixton area of South London, has proven a hit with locals and the media.

Prominent UK actors such as Lenny Henry (Harry Potter And The Prisoner Of Azkaban) and Adrian Lester (Hustle) are among those to laud the stunt on social media.

By yesterday evening the posters had been taken down and replaced with adverts for McDonald’s. But not before the campaign caught fire and reminded us of the serious message at its heart. How can people feel an equal part of society if they only see one type of star on screen? Recent research by the British Film Institute shows that black actors played only 218 lead roles in the 1,172 British films released between 2006 and 2016 and black actors played less than 1% of the total available roles. More than half of UK films made over the past 10 years do not have black actors in any role and only 15 black actors have played two or more lead roles in films since 2006.