An investigative website has said it is planning to release the true identity of the second man accused of poisoning Sergei Skripal with deadly Novichok.
The Parliament meeting is scheduled for October 9, the advert said.
The website already claims to have unmasked Ruslan Boshirov, one of two men named by the UK as suspected of poisoning the Skripals, as a decorated Russian colonel.
But the true identity of his alleged accomplice Alexander Petrov had remained a mystery.
The public meeting is being hosted on Tuesday by Isle of Wight Tory MP Bob Seely, a member of the Commons Foreign Affairs Committee.
It was advertised online today with the title "Announcement of the Identity of Second Skripal Suspect". The advert said it would be held in a House of Commons committee room.
It was not immediately clear whether Bellingcat already had the information, and if so, why it was waiting four days to publish it. Parliament only resumes sitting on Tuesday.