Missing Belgian backpacker Theo Hayez.
Missing Belgian backpacker Theo Hayez. Contributed

MISSING: Who is Theo Hayez?

THEO Hayez has captured the hearts of hundreds of Byron locals, with many giving up their time to help search for a person they've never met.

The 18-year-old Belgian backpacker was last seen in Byron Bay on May 31 leaving Cheeky Monkeys nightclub on Jonson St.

Since then, hundreds of people have joined police in a search for the Theo, but who is the man they are all searching for?

Theo Hayez is a son, a big brother, a cousin, a god son... and more.

His parents describe him as a conscientious, smart and kind boy, who cares for his family.

His mother, Vinciane Delforge, told Belgian broadcaster RBTF her son's disappearance was out of character.

"From the beginning I thought something had happened to him, a bad meeting or an accident.

"He's a very organised boy, very well balanced. would never have acted improperly ... I'm hopeful but I'm realistic."

His father, Laurent Hayez told the ABC Theo is "a very clever guy" and plans to study engineering at university in Belgium after his travels.

Theo had also planned on helping his father, who works in the music industry in Europe, set up a band when he returned home.

Having studied at at Athénée Royal d'Auderghem, a secondary school in Brussels, Theo embarked on a trip of a lifetime to Australia.

Theo had been travelling in Australia for eight months, backpacking across the country visiting places like Darwin and Alice Springs before arriving in Byron Bay a day before he disappeared.

He was was due to fly home back to Belgium on June 12.

His cousin Lisa Hayez, who travelled with Theo earlier in the year, posted on Facebook: "Days before his disappearance, he told his family that he was impatient to come home. We have grave concerns for his safety".

Theo is described as being of Caucasian appearance, approximately 180cm to 190cm tall, with a thin build and blond hair.

He was last seen wearing a black hooded jumper, beige pants and black shoes leaving Cheeky Monkeys on May 31.

Anyone with information should contact Crime Stoppers on 1800 333 000.