Ackergill Tower, on the north-east coast of the Scottish Highlands, was forced to close after a blaze caused severe smoke damage throughout the castle in January.
The blaze took root in the cellar, which was destroyed, and police still treating the cause of the outbreak as suspicious.
The castle has since been fully refurbished, and now features 35 bedroom suites, four self-catering cottages and the largest treehouse in Europe, set in 3000 acres of scenery.
Founder of castle owners AmaZing Venues Mike Clare said: “From the moment a guest arrives at Ackergill Tower we want them to feel that this is where their Scottish Highland adventure begins.
“This castle is like a living and breathing museum, and our job with this refurbishment, has been to safeguard the many treasures within it.”
Ackergill Tower has acted as a retreat for celebrities such as Jack Nicholson, Michael Douglas and Billy Connolly in the past.
VisitScotland chairman Mike Cantley said: “We are delighted with the work carried out to restore and revitalise Ackergill Tower.
“Our private venue partners play a crucial role in attracting tourism to the area and the Tower continues to provide an inspiring and beautiful destination and reason to visit the Highlands.”
Ackergill Tower’s general manager Craig Wright added: “The property has never looked so good and now as we enter springtime we encourage visitors both locally and from further afield to sample our hospitality and incredible grounds.”
The castle boasts a rich history. The style of architecture suggests that the tower was built around 1475, and the building was first owned by the Keith family.
The family engaged in a bloody feud with the local Gunn family, after which Helen Gunn was abducted by a member of the Keiths and taken to the castle.
Helen reportedly jumped or fell from the castle tower trying to escape, and it is claimed that she can be seen in spirit as a green lady, or as a lady in a long red ball gown with tall black hair.
In 1651, Oliver Cromwell reportedly used Ackergill to garrison troops during the siege of Dunnottar Castle.