President of the European Parliament Antonio Tajani revealed Zuckerberg's Brussels stop in a press release on Wednesday.
Collins said that Cummings would be reported for failing to appear, which "could result in a decision that a contempt of parliament has been committed, a very serious outcome for the individual".
Facebook (FB +0.3%) CEO Mark Zuckerberg heads overseas to meet with the European Parliament on Tuesday evening, where he'll discuss the use of personal data of the company's European Union users.
Zuckerberg's already gone before the US Congress.
His concern and even frustration that the leadership of the EP agreed to hold a meeting behind closed doors, was expressed by a number of parliamentarians. "It is a step in the right direction towards restoring confidence".
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Members of the public also won't be able to form their opinions about Zuckerberg's answers to the members of the parliament.
Věra Jourová, the European Commissioner for Justice, Consumers and Gender Equality, said on her Twitter profile that she is glad to see Mark Zuckerberg accept this invitation but that it is pity it will not be a public hearing since many Europeans deserve to know exactly how their data is being handled.
The news comes a month after the parliament invited Zuckerberg to appear before three of the assembly's committees.
This after revelations that political consultancy Cambridge Analytica improperly accessed details of millions of Facebook users.
But he will not appear before the British parliamentary committee investigating the matter, but rather has agreed to appear before the European parliament at a closed-door meeting.
A DCMS committee spokesperson confirmed no formal summons has been issued to Zuckerberg to date, although Vote Leave campaign director Dominic Cummings, and former Cambridge Analytica CEO Alexander Nix - both embroiled in the burgeoning scandal over the alleged misuse of data in political campaigns - were subject to formal summons.