McGregor (21-3) won the UFC's 145-pound title in December, when he knocked the Brazilian Aldo out in 13 seconds at UFC 194, but he never defended the belt. The Irish star opted for a pair of welterweight fights against Nate Diaz in 2016 before challenging Eddie Alvarez on Nov. 12.
The decision made room for Aldo (26-2), who defeated Frankie Edgar for the interim featherweight title at UFC 200 in July, to be elevated to undisputed champion.
"I knew for certain that this would happen," Aldo, widely considered one of the greatest fighters of all time, said in his first public comments about McGregor ceding the featherweight belt. "In my opinion, I never stopped being the champion. I lost that fight because of an accident."
Despite succumbing to McGregor in his first loss in more than 10 years, Aldo insisted to UFC Brazil that he was the better fighter and would win a rematch.
"I knew that I would win a rematch and would become champion again," Aldo said in Portuguese. "It's not my fault that he's a coward. He was never the champion. I don't see myself losing to anyone in my weight class or any other one."
Aldo, who campaigned for a rematch against McGregor all year before publicly asking the UFC for his releaseafter the Alvarez-McGregor fight was announced in September, said he is intent on moving up to the 155-pound class and getting a rematch with the Irish superstar.
"It's logical that I give a lot of thought to that rematch, and it's a certainty that it will happen," he said. "But I want to defend my [featherweight] belt first. Then I can start preparing to face McGregor [at lightweight]."
However, before he can get a rematch with McGregor, Aldo will most likely first face the winner of the interim featherweight title fight between Max Holloway and former lightweight champion Anthony Pettis in a unification bout, which will be contested at the UFC 206 main event on Dec. 10.
"I will be prepared to fight whoever wins that fight," Aldo said. "It's clear that Pettis has a bigger name -- he already was the champion. It would be a big fight. But if it goes the other way, I don't have a problem with that either. I will win either way."