Actress Carey Mulligan has appealed to Theresa May to bring an end to the suffering of children in Syria.
As part of a new video campaign for War Child, Carey was joined by other celebrities to mark seven years of fighting in Syria.
She wants the government to show how they will help those affected by war.
“The prime minister needs to come to parliament with a clear plan to help bring this brutal conflict to an end,” she said.
“The UK must outline what it will do to put pressure on the Syrian regime to stop fighting.”
The Enough is Enough video also features Sam Smith, James Bay and Nicole Scherzinger.
It follows 17-year-old Syrian girl Fatima who escaped her home with her family when the conflict broke out and is now living as a refugee in Jordan.
Fatima also describes how she felt when she found out her brother had been killed.
Carey, a global ambassador for War Child, visited Fatima as part of a trip to meet Syrian refugees.
She described her as “an inspirational and intelligent young woman, full of passion and honesty”.
“She had the courage to talk about her experience of the war in Syria and what she had witnessed – something no young girl should have to go through.”
As part of the video release, War Child has released a report called Six Years On – A War On Syria’s Children, which says that more than 400,000 people have been killed since the conflict began.
They also estimate that up to 55,000 children have died during the war, which is about to exceed the length of World War Two.