As part of his new role, Alex will raise the profile of mental health education and wellbeing in schools.
Since Alex left the villa in 2018, he has returned to work as an A&E doctor at Lewisham Hospital in south east London and has treated coronavirus patients on the frontline.
He has also been a passionate online campaigner for children's mental since he tragically lost his brother to suicide last year.
As Youth Mental Health Ambassador, he will use his clinical expertise and personal experience to help shape policy on improving support for young people in schools, colleges and universities.
The past year has been incredibly difficult for young people, whose lives and education have been upended by the pandemic and the lockdowns
He will also sit on the new Mental Health in Education Action Group, chaired by Children's Minister Vicky Ford and Universities Minister Michelle Donelan. This group will look specifically at how the government support young people with their wellbeing as they return to school and university after the disruption caused by coronavirus and the lockdowns.
"The last year has been unimaginably difficult for all of us, but particularly for young people who have sacrificed so much," said Alex.
"I am honoured to be appointed for this role where I'll be working closely with government to make mental health an absolute priority and hope to have a positive impact on the lives of young people and their education for good.
"Right now young people need a voice in government, and I hope that through this role I can advocate for meaningful change in this area."
Thanks to his huge social media following, including 1.6m Instagram followers and 91.6k YouTube subscribers, Alex is well equipped to signpost the support that is available as well provide tips and feedback to the government for what more can be done to help young people.
Alex's new role comes on top of the existing support the government is providing to ensure children's mental health is a priority, including the Wellbeing for Education Return project, which provides funding to councils so they can offer training and advice from mental health experts to schools and colleges on how best to support their pupils.
Alex will start his new role immediately, and will work within the Department for Education. He will remain independent of government and it's an unpaid position.
Claire Murdoch, Mental Health Director, NHS England and NHS Improvement, said: "It has been a tough year, but the NHS is here for children's mental health, and with the help of Dr Alex and our partners in health, education and charities, we will keep working hard to make sure every child in this country get the mental health support that they deserve."
Prime Minister Boris Johnson said: "Children and young people have heroically adapted to save lives and protect our NHS. This has understandably had a huge impact on their mental health, so I want to shine a spotlight on this vital issue ahead of their return to school.
"I'm delighted that Dr. Alex George will be working with us as we do everything in our power to improve people's mental wellbeing."