Nick Clegg and his wife Miriam Gonzalez Durantez have revealed their eldest son's secret battle with blood cancer.
The couple told ITV's Lorraine Kelly that telling their 15-year-old son Antonio he had Hodgkin lymphoma was one of the "toughest things" they've had to do.
He found a small, painless lump in his neck and tests revealed he also had lymphoma across his chest when he was diagnosed in September last year.
After receiving treatment on the NHS at University College Hospital in London, including four monthly cycles of chemotherapy and heavy steroids, he is now in remission having suffered severe side effects including hair loss, vomiting and fatigue.
Former Lib Dem leader and deputy prime minister Mr Clegg said: "His lymphoma was all over his chest and his neck.
"He gets tested every three months, I think for a couple of years, so there is always a slight spike of anxiety with us every three months, but basically he is on the road to recovery.
"Interestingly, the thing he was most concerned about was sort of falling behind his classmates.
"His anxiety was more about keeping up with his classmates, keeping up at school. So it was very impressive actually."
He added the couple's other children, Alberto and Miguel, had taken the news well.
The couple are now raising awareness of the charity Bloodwise, which is urging more research into less toxic treatments for children with cancer.
Blood cancer is most common among children and young people, with more than 1,100 of those under 24 diagnosed in the UK every year.
Dr Alasdair Rankin, director of research at Bloodwise, said: "The reality is that one in five children diagnosed with the most common type of leukaemia still do not survive, and that those who do often experience devastating side effects both during and after treatment.
"This is simply not good enough. We need to save every child's life, make the treatment process much kinder and give them the life they would have had without cancer."