Comedian Sacha Baron Cohen and his wife, actress Isla Fisher, have donated £670,000 ($1m) to two charities.
The couple have given £335,000 to Save The Children to help vaccinate against measles in northern Syria.They are also giving the same amount to the New York-based International Rescue Committee, run by former UK foreign secretary David Miliband.
This will fund education, health care, shelter and sanitation for refugees in Syria and neighbouring countries.
More than 250,000 people have been killed since an uprising against President Bashar al-Assad began in March 2011 and more than 11 million others have been forced from their homes.
Mr Miliband said those caught up in the conflict were "victims of terror".
He added: "Sacha and Isla's donation is a great expression of humanity, and a challenge to do more for the most vulnerable.
"I hope it is an example to many others seeking practical ways of making a difference during the Christmas and new year season."
Justin Forsyth, CEO of Save the Children, said Syria's health system had collapsed and deadly childhood diseases such as measles had returned, threatening the lives of many children.
"By allowing us to make their generous donation to Syrian children public, Sacha and Isla are helping highlight the tragedy of the issue today," he said.
"These are desperate times for Syrian families facing bombs, bullets and torture in Syria. The couple's donation will save many thousands of lives and protect some of the most vulnerable children."
