Twelve tanks rolled through a city centre, past crowds of shoppers, as the Prince of Wales took the salute from a parade of soldiers and veterans.
Hundreds of people packed the centre of Newcastle as members of The Queen's Own Yeomanry (QOY) paraded.
The crowds, not put off by persistent drizzly rain, applauded as the troops passed Grey's Monument led by the Band of The Royal Regiment of Fusiliers.
They were followed by veterans and 12 Scimitar light tanks.
The Prince, who was wearing combat uniform, is the Royal Honorary Colonel of the regiment - an armoured territorial army unit which is celebrating its 40th anniversary.
Charles got a kiss from one woman in the crowd as he went on a short walkabout, while a little boy dressed in full uniform with Black Watch headgear was honoured with a royal salute from the Prince.
Thomas Farrell, six, from Washington, said he told Charles he wants to be a tank driver when he grows up.
Also at the Monument, the Prince met families of some of the soldiers from the unit who are currently heading out to Afghanistan.
Karen Hunter said her husband, Sgt Neil Hunter, was already out there.
Mrs Harrison said: "He was very interested in how my husband was finding it out there - how he was coping with the hot weather and everything. I just think it's good to know he's so supportive of the troops. It's also nice for all these people here to see that."