After graphic novels and featuring in a Hollywood movie, the couple overseeing Tintin's legacy have now built a private museum that celebrates the glory of his creator Herge and are hoping to further build the Tintin brand.
"Our work is to educate people, inform people," said Nick Rodwell, who married Herge's widow Fanny Vlamynck around a decade ago.
"We're creating a Tintin brand that lies somewhere between graphic novel and contemporary art," Rodwell added in a rare interview inside the Louvain-la-Neuve museum that he and Fanny built five years ago.
"If I die tomorrow I'll know the work has found its right place."
Designed by Pritzker prize-winning architect Christian de Portzamparc and opened in the leafy new university town of Louvain-la-Neuve, some 20 kilometres (12 miles) outside Brussels, the museum sees some 80,000 visitors a year.
"Schools, foreigners from across the world, Tintinophiles and Tintinologists," Rodwell said.
"It was a huge investment but it's given us credibility," he said of the 15-million-euro ($20 million) project. "Museums don't make money but we break even."
The museum is largely dedicated to Herge's artistic skill, with a restaurant and quality memento shop --more art-house for adults than comic-strip fantasy for kids, a vision that seems to be paying off.
As Tintin's fame spreads, Herge's original drawings are selling like hotcakes at auction, a double-page ink by the Belgian artist from 1937 going for 2.1 million euros in Paris late last month.
But with the museum housing a mere 10 percent of their legacy, the couple are hoping to organise temporary shows elsewhere, notably at the Cheverny castle in France's Loire valley that inspired the Moulinsart castle in the original work.
The fame of the intrepid boy reporter with the quiff, a children's bedside classic in much of Europe, spread when Steven Spielberg rolled a Hollywood blockbuster in 2011 co-produced with "Lord of the Rings" director Peter Jackson.
It was "gigantic, the best promotion possible" for Tintin, Rodwell said, though only a tepid success in Hollywood terms, ringing up 374 million dollars in contrast with a target of 600 million.
Jackson is planning a sequel, he said, but is currently tied up with "The Hobbit" until 2017 and "has asked for time."
Should he fail to release a new Tintin movie within five or seven years of the last one, "we will recover the rights."
Herge, real name Georges Remi and one of Belgium's most beloved sons, died childless in 1983 at age 75, leaving his estate to Fanny Vlamynck, a colouring artist 28 years his junior.
She has so far stuck steadfastly to Herge's wishes not to hand over the boy hero to another but Rodwell said the couple needed to plan for January 1, 2054 when the copyright will become public domain.
"We must release a new album in 2053 either to extend the copyright, as was the case with Mickey Mouse, or to open up the right path for those who want to continue Tintin's adventures," he said.