Ewan McGregor, Michael Sheen and Tom Hiddleston are among the stars who have lent their support to Unicef's Christmas campaign.
Rita Ora, Tinie Tempah and Emma Bunton have also voiced their concerns about the plight of displaced Syrian children facing a third bitterly cold winter in refugee camps in a video, which aims to raise awareness of the crisis facing the citizens of Syria.
Ewan, Unicef UK ambassador, said: "My heart truly goes out to the millions of Syrian children who have lost everything: their families, friends and homes. Facing a third year in a freezing cold camp is no place anyone should call home, let alone a child. I worry that the world is starting to shut its eyes to the Syrian crisis."
Rita revealed that shooting the video reminded her of her own experiences.
"When filming Unicef's No Place Like Home video I kept thinking of Pristina, my home town in Kosovo. The city has seen its fair share of trouble but thankfully that's over now," she said.
"But right now, children in Syria are suffering unspeakable violence, often fleeing their homes with nothing but the clothes on their back. Now facing a third winter in cold tents, their lives are threatened by the freezing temperatures."
Michael recalled his trip to Lebanon with the charity. He added: "Last month I travelled to Lebanon with Unicef and met Syrian children struggling to cope in desperate circumstances.
"As the bitter winter closes in, they are being pushed to the edge of their physical and psychological endurance. No child should be living like this."
:: The UK Government will match pound for pound all public donations made to Unicef's work for the children of Syria until January 31 2014. Text WARM to 70111 to give £3 or visit unicef.org.uk.