Wilmots, the last man to score a goal for Belgium at the FIFA World Cup back in 2002, revealed last week that he had yet to complete the formalities of signing a new contract.
On Wednesday, following Belgium's first training session in Brazil ahead of the finals, he announced that the deal had been done, with the new terms committing the 45-year-old up to 2018.
"I've signed," he told reporters. "Vital (Borkelmans, assistant coach) and Mario (Innaurato, physical trainer) have extended their contract a few days ago, and also the doctor (Kris Van Crombrugge).
"With Lieven (Maesschalck, rehabilitation coach) there is an agreement, but the signature is missing."
Wilmots also took time to comment on the fitness of his squad, with Romelu Lukaku a previous injury worry due to a minor ankle problem.
The coach assured fans that the Chelsea striker would be fine for Belgium's Group H opener with Algeria on Tuesday.
"All minor aches are gone," he said. "Our first session was prevention training.
"After two days off and a long flight I wanted to not take risks.
"(Lukaku) does not suffer more, his injury is a thing of the past."
