Kasabian appeared dressed in white overalls to paint the numbers "48:13" on a wall in East London yesterday (4 April.)
Lead singer Tom Meighan was joined by guitarist Serge Pizzorno on Dalston's Kingsland Road to paint the cryptic message in black paint on a neon pink background. Not happy with just one mystery, the pair also had overalls that, when put together, read "MALTED MILK."
Kasabian were yesterday revealed as the first headliners of this year's Glastonbury Festival, news of which received mixed reactions from festival-goers.
Since the strange graffiti appeared yesterday, fans have taken to Twitter to share their theories on its meaning.
"Kasabian paint cryptic message on London wall" IT SAYS 48:13 YOU GUYS HOW AM I THE ONLY ONE THAT THINKS ITS THE ALBUM LENGTH COME ON— Mr. Brightside (@MetallicYoshi64) April 4, 2014
Kasabian 48:13 .New single release maybe maybe not ????— Birdybiffyclyro (@birdybiff) April 4, 2014
The building belongs to artist and fashion designer Aitor Throup, who designed the cover art for Kasabian's 2011 album Velociraptor! and directed the video for 'Switchblade Smiles.'
In an interview with NME outside the studio yesterday, Throup refused to reveal the meaning of the artwork, but said it woul be "part of something bigger."
Throup also added: "I don't think Tom's ever picked up a paintbrush in his life. He has good graffiti skills, but Serge was a bit better with a roller.
"I'll give you one clue to what it all means. Malted Milk. Like the biscuits. You'll see." We have no idea either.
Kasabian will headline the Pyramid Stage at Glastonbury Festival on 29 June. They're also set to appear at several European festivals, as well as Sonic Mania in Japan.