Rob Rinder shared his family's experiences of surviving the Nazis when he spoke at Durham Cathedral on Friday.
The TV personality and barrister was leading Durham council's Holocaust Memorial Day commemorations.
'Judge' Rinder said the occasion invited all to "reflect on the fragility of freedom".
During a powerful speech, he also spoke about his grandfather, who was one of 300 'Windermere children' to arrive in the Lake District after surviving the Holocaust.
Rinder said the young people that listened to the stories of his family and others like them would "leave feeling courageous".
He added: "They will go into the world understanding how democracy requires each and every one of them to preserve, to protect and to defend it."
Mr Rinder's Lithuanian grandfather Morris arrived in the Lake District with hundreds of other children after surviving the Nazis.
The Jewish youngsters who became known as the 'Windermere children' had been saved by British liberation forces from death camps.
They were orphans, their families lost to the Holocaust that killed six million Jews across Europe.
The celebrity's heartfelt appearance at Durham Cathedral marked the beginning of commemorative events in the city.
The cathedral, which was lit up purple to mark Holocaust Memorial Day, is hosting the 'Surviving Belsen' display until Sunday, along with an exhibition reflecting the killings of Gypsies during the Second World War.