Transport for London (TfL) is trialling a new initiative to make journeys more comfortable for those with hidden disabilities and conditions.
Much like the Baby on Board badge, the new badge and card will help those less able to stand get a seat if and when they need one, and will be spotted around the capital from September.
The blue badges will read "please offer me a seat" while the cards will carry the message "remember not all disabilities and conditions are visible".
The badges can be worn on passengers' clothing while the card is handed to TfL staff - and there's absolutely no pressure to explain to fellow passengers the reason for needing the seat.
TfL is looking for 1,000 people to trial the new badges and cards for six weeks to assess whether they actually help secure a seat, and gauge how the rest of the public react.
The trial will kick off on Monday September 12 and, if successful, the badges and cards will be rolled out later in the year.
Mayor of London Sadiq Khan said: "We hope that these new blue badges can make a real difference to those who find it difficult to get a seat when they need one, particularly those with hidden disabilities.
"Everyone who travels around London knows about the success of the Baby on Board badges. I want Londoners to embrace our new trial and help these blue badges become as instantly-recognisable, giving confidence to those wearing them on public transport across London."