Will Smith has urged the public to think about those who “don’t have a place to call home” in a video promoting a mass sleep-out to help end homelessness.

The Hollywood star, 51, is joined by Dame Helen Mirren, 74, and Coldplay singer Chris Martin, 42, in calling for people to support The World’s Big Sleep Out.

The international event aims to see around 50,000 people spending the night outside in their respective cities on December 7 to raise awareness of the issue.

View this post on Instagram

Ask yourself this question: what does home mean to you? Maybe it's comfort & security, maybe it's family, love & warmth. But there are over 100 million people in the world with nowhere to call home. . Join @willsmith, Dame @helenmirren & Chris Martin from @Coldplay in calling for an end to global #homelessness. On December 7th, 50,000 people will sleep outside in 50 cities around the world. And we need your help. . Register now to take part in the world’s largest display of solidarity & help raise $50 million to help one million #homeless people globally. . Head to LINK IN BIO ⬆️ to sign up to one of the official #BigSleepOut events, or to host your own. . You CAN make a difference. The time has come to #endhomelessness. . . . #homelesspeople #homelessnothopeless #helpthehomeless #homelesslivesmatter #homelessnessawareness #charityevent #charitychallenge

A post shared by The World's Big Sleep Out (@worldsbigsleepout) on

In the minute-long video, Smith says: “Think for a minute about what home means to you. For me home means conversation.

“It’s the place where my family comes together and that’s the most beautiful part of home.

“But there are over 100 million people in the world that don’t have a place to call home.”

Dame Helen says: “On December 7 2019 we are hoping for 50,000 people to sleep out in the world’s largest display of solidarity and support for homeless and displaced people.

Social Bite’s charity sleep-out in Princess Gardens in Edinburgh (Social Bite/PA)

“Major sleep-out events will be happening in Trafalgar Square, in Times Square and in 50 cities across the world.”

Martin adds: “Thank you for choosing to sleep out this one night and helping out so many people who don’t have a choice.”

Cities taking part in The World’s Big Sleep Out include London, New York, Edinburgh, Chicago, New Delhi, Newcastle, Dublin, Belfast, Madrid, Barcelona, Brussels, Cardiff and Santiago.

Smith will read a bedtime story in New York’s Times Square while Dame Helen will do the same in Trafalgar Square, London.

Social Bite co-founder Josh Littlejohn
Social Bite co-founder Josh Littlejohn (Social Bite/PA)

It is hoped the initiative will raise more than £38.7 million (50 million dollars) which will be distributed to a range of homelessness and refugee focused charities around the world.

Organisers Social Bite started as a sandwich shop in Edinburgh in August 2012 and have since opened multiple branches.

A quarter of its staff are homeless and the charity has received visits from Hollywood stars Leonardo DiCaprio and George Clooney.