Angelina Jolie has donated an undisclosed sum to two British children who are running a lemonade stand to raise money to help people suffering due to the humanitarian crisis in Yemen.

The British schoolboys, six-year-olds Ayaan Moosa and Mikaeel Ishaa from east London are best friends and set up the stand to raise funds for charity in July after learning about the crisis.

Ayaan Moosa's father, 37-year-old Shakil Moosa, told CNN the "Maleficent" star contacted the family via an agent three weeks ago and offered to make a donation to the cause, which was transferred this weekend.

Jolie also sent the children a letter, which they shared on Instagram, thanking them for their efforts and apologizing that she could not be there in person to buy their lemonade.

"She's been so amazing. It's surreal she's not just a random star, you're talking about one of the top names on the planet so it's a bit overwhelming," Moosa said.

"She's phenomenal."In a video in Instagram, the children thanked the actress.

"Hi Angelina, I'm Ayaan. And I'm Mikaeel. And we're the LemonAid boys.

"We just wanted to say thank you for donating to our cause," they said in the video.

They added they'd be happy to sell her a glass of lemonade next time she was in London.

View this post on Instagram

Thank you message for @angelinajolie.offiicial 💙 #yemen #lemonaidboys #yemencrisis #angelinajolie

A post shared by Ayaan & Mikaeel (@lemonaidboys) on Sep 8, 2020 at 7:07am PDT

Jolie, who is a Special Envoy for UNHCR, the UN Refugee Agency, has previously spoken out about conflict and poverty in the Middle Eastern country, which has been beset by civil unrest for decades.

From 2015, a five-year civil war has pitted Houthi rebels against the internationally recognized government, which has been backed by the UAE and Saudi Arabia, killing an estimated 112,000 people.

It has been estimated that half of Yemen's population is at risk of famine, with millions hungry, starving or malnourished.

The country has also been gripped by disease, with tens of thousands of people have contracted cholera and now there are concerns that it could suffer one of the worst coronavirus outbreaks in the world.

When Ayaan and Mikaeel heard about the plight of young children in the country, they wanted to help, Ayaan's father told CNN.

View this post on Instagram

We really are the best of friends 💙💙 #lemonaidboys #yemen #lemon #prayforyemen

A post shared by Ayaan & Mikaeel (@lemonaidboys) on Aug 10, 2020 at 2:45pm PDT

"They were gobsmacked that people were living like that. It's the first time in their lives they realized not everybody is living like them," Moosa said.

"They were keen to do something ... and decided whatever couple of hundred pounds we made, we would give to a charity."

The children have now helped to raise £70,000 ($90,944) alongside joint fundraising efforts from friends and family. They now hope to be able to raise £150,000, Moosa added.