Mohamed Abrini has admitted to being the 'man in a hat', seen on security camera footage at Brussels airport, authorities said on Saturday.
Prosecutors said that after being confronted with footage prepared by an investigational unit, Mr Abrini said he was the man police had been hunting since the 22 March bombings which killed 32 people.
He has also been charged over his suspected role in the Paris attacks in November 2015, in which 130 people died.
A spokesman for Belgium's public prosecutors said Mr Abrini had no other choice" but to confess.
"He is charged with participation in the activities of a terrorist group and terrorist murder," the Belgian federal prosecutors office said in a statement.
"After being confronted with the results of the different expert examinations, he confessed his presence at the crime scene.
"He explained having thrown away his vest in a garbage bin and having sold his hat afterward."
Two men arrested alongside him during a raid in Brussels yesterday were released after questioning but three other suspects have been charged with terror offences.
A man named by prosecutors as Osama K has been identified as a suspect seen with suicide bomber Khalid El Bakraoui shortly before he blew himself up at Maelbeek Metro station.
Identified as Osama Krayem by Swedish media, he is known to have fought for the so-called Islamic State in Syria and attempted to recruit jihadists in his home city of Malmo.
Investigators said he was also present at a shopping centre when the suitcases used to contain the deadly explosives were purchased.
He remains in custody and has been charged with participation in the activities of a terrorist group and terrorist murders.
A Rwandan national arrested at the same time, named as 25-year-old Hervé B.M., has been charged with the same offences, as has fourth man - Bilal E.M - after being accused of aiding Abrini and Krayem.
Numerous searches were carried out on Friday night as investigations continued, including at the suspects’ homes in Anderlecht and Laeken.
A new operation was launched on Saturday at a suspected safe house in the Rue des Casernes, Etterbeek.
No weapons or explosives were found, a spokesperson for the federal prosecutor’s office said.
Abrini was the last named suspect from the Paris attacks to remain on the run following the arrest of Salah Abdeslam in March.
The pair are childhood friends, having grown up together in Molenbeek, and were caught on CCTV in a car together just days before the Paris attacks.
Abrini, a 31-year-old Belgian national of Moroccan origin, was seen driving a Renault Clio used to ferry Isis gunmen around Paris and was the subject of a European arrest warrant calling him “dangerous and probably armed”.
His DNA was also found in the flat on Rue Max Roos, in Schaerbeek, from where the airport bombers caught a taxi on the morning of the Brussels attacks.
Abrini was previously known to police for thefts and drug-related offences but is believed to have travelled to Syria, where his younger brother died fighting for Isis in 2014.
He is also reported to have travelled multiple times to the UK, meeting with several men suspected of terrorist activity in Birmingham, and taking photographs of an as-yet-unidentified football stadium.
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