Captain Alwyne Farquharson, 16th Laird of Invercauld, will turn 100 on May 1 with the occasion to be marked at Braemar Castle on Deeside.
The chief of Clan Farquharson has held the role for 70 years with the community to mark his special day in his honour.
He gifted Braemar Castle to the community 11 years ago with the attraction since flourishing as a visitor attraction.
Simon Blackett, chair of Braemar Community Limited and former factor of Invercauld Estate, said: “We’re not sure if May 1st will make Captain Farquharson the oldest Clan Chief in Scotland but think it very likely.
“The Laird won’t be able to join us on the day, but we will have a community party and birthday cake to celebrate”
Braemar’s oldest inhabitant, Zan Grant, will do the honours and cut the cake on the Captain’s behalf.
Mr Grant worked as Captain Farquharson’s secretary when he first became Laird in the 1940s and is now 92 years old.
Captain Farquharson is the laird of Invercauld Estates but spends much of his time in Norfolk.
He assumed the title in 1941 after his aunt, Myrtle Farquharson, was killed in a London bombing raid.
The captain served with distinction as a Captain in the Royal Scots Greys during World War Two.
Following the war, as he recovered from his injuries at his father’s home in Yorkshire, he met his first wife Frances, a fashion editor with Vogue in the United States,
She visited Braemar Castle to help organise its contents and the two soon fell in love and married, with the laird’s new wife famously painting parts of the castle’s exterior pink.
Captain Farquharson is due to visit Braemar at the end of the month to open a new pub, Farquharson’s, in the village.
Castle Manager, Georgina Errington says “Captain Farquharson is a regular visitor to the Castle and is very supportive of the community effort.
“We know many people will want to be part of the celebration.”
Clan Farquharson branched from Clan Shaw in the 16th century and the first Clan Chief, Finlay Mhor was standard bearer for Mary Queen of Scots at the Battle of Pinkie in 1547.
The 9th Laird of Invercauld stood alongside the Earl of Mar when the standard was raised to start the 1715 Jacobite rebellion in Braemar.
Over the centuries, the Clan has spread worldwide and each year many return to visit their Clan seat and to walk in the footsteps of their ancestors.
The trust that runs the castles is in the process of raising £1.6m to replace the damaged harling at the landmark and are attracting support from clan members worldwide.
The clan chief’s birthday will also be celebrated at the Ballater Highland Games in August.