The two brands have joined Tesla as confirmed attendees, while the show's organisers are believed to be still attempting to sign up other manufacturers.
MG is the first manufacturer to sign up, and will be displaying its two main models, the MG 3 and the MG 6, at the show. While the manufacturer says that it has “several models planned for the immediate and longer-term future”, it has not confirmed whether any of these will be appearing at the show in the form of concepts or production models.
Mazda, however, will be represented at the show by dealer group T W White & Sons. The group, based in the south of England, will be displaying a selection of Mazda’s new range, with the 2, 3 and MX-5 all expected to be on show.
The dealer group has also confirmed that the MX-5-based Mitsuoka Roadster will also be on display at the show.
At a previous press event for the show, HRH Prince Michael of Kent announced that Aston Martin, Jaguar, Land Rover and Geely had agreed "multi-million pound" investments to exhibit at the revived London motor show in May 2016.
However, a spokesman subsequently clarified the comment, making it clear that the Prince actually meant to acknowledge these three firm's investment in the UK car industry.
The show will run from 5-8 May 2016 with adult tickets priced at £13. No prices for concessions were revealed, but they were said to be "substantially lower". Prince Michael said the goal is to make the show "rank alongside cities like Geneva and Frankfurt".