News broke today on big Brazilian news outlets and the official Rio di Janeiro Instagram page that Madonna is doing a special free concert there in May.
https://oglobo.globo.com/blogs/lauro-jardim/post/2024/03/show-de-madonna-em-copacabana-esta-confirmado-e-deve-ser-o-maior-de-sua-carreira.ghtml
(Non translated link)
This may just be to close the tour she’s on, but it may be relevant to Glastonbury as it does extend things further than expected, especially if Madonna is open to doing something for a lower fee (free in this case!).