Mr O'Callaghan-Westropp was on honeymoon in Greece with his wife Zoe Holohan
The Department of Foreign Affairs has confirmed the death of an Irishman in the wildfires in Greece.
Brian O'Callaghan-Westropp was on honeymoon with his wife Zoe Holohan in the coastal town of Mati near Athens when the fires erupted.
Ms Holohan is currently recovering in a Greek hospital.
The couple were married last Thursday before flying to Greece over the weekend.
They became separated trying to flee the wildfires on Monday - Ms Holohan made it to a beach and was admitted to hospital with burns, however Mr O'Callaghan-Westropp had been missing ever since.
Ireland’s ambassador to Greece Orla O'Hanrahan has extended her sympathies to booth families.
In a statement the families said: "We are deeply saddened to confirm the death of our family member, Brian O'Callaghan-Westropp.
“The families would respectfully appreciate privacy at this time as we grieve and as Zoe makes her recovery.
“Funeral arrangement will be announced at a later stage."
Mr O'Callaghan-Westropp - who was originally from Newmarket on Fergus in Co Clare - volunteered at Blood Bikes Dublin and has been described as selfless, who always thought of others before himself.
At least 80 people have died in the fires, with almost 200 others in hospital. 23 children are among the injured.
As many as 40 people remain unaccounted for, with soldiers going house-to-house, checking for victims.
It has been described as a "national tragedy" and the country has declared three days of mourning.
It has emerged that anti-terror police are investigating whether one fire, which spread through the eastern resort of Mati, was a matter of arson.
Some residents believe it may have been the result of a crude attempt to clear forest land and make space for building projects, but police are yet to determine a cause.
Before the blaze, the area was dense with thick pine, which - combined with strong winds - allowed the flames to spread extremely quickly.