The world-famous musician urged Observer readers to continue to be vigilant as lockdown measures ease after a friend, who despite having both doses of the vaccine, contracted Covid this week.
Speaking to this newspaper, Brian said: "My message to everyone really is even if you're vaccinated - be careful. Don't think that the bombs have stopped dropping and don't be as insanely optimistic as Boris."
This comes as Boris Johnson is set to lift all Covid restrictions on so-called 'Freedom Day' on July 19.
He made the comments during a visit to Selsey yesterday as he unveiled the first of five seal sculptures, designed and created by Chichester College students, form part of a 'seal trail' through the town.
Read more here: Here's why Queen guitarist Brian May was in Selsey today
The sculpture was dedicated to the late astronomer and presenter Sir Patrick Moore.