In her post, the singer revealed that a new music video would be dropping on Monday at 10 a.m. She added, "I finally got to work with the brilliant, brave, & wickedly funny [Blake Lively] on her directorial debut."
On her own accounts, Lively simply wrote, "Tomorrow. 10am ET," alongside the little "shh" emoji.
The teaser trailer, which is just 10 seconds long, shows a delicious-looking red velvet cake with some vicious claw marks through it.
A hand — which fans believe could be Lively's — then appears and grabs a chunk of the cake. A sneak-preview image from the video also shows the singer dressed in a dramatic red dress, holding a guitar under a chandelier. Mysterious, eh?