Taylor Swift's Ex Shares Bloody Childhood Prank That Left His Neighbors 'In Tears'

Joe Alwyn revealed Friday that he once got in serious trouble with British authorities — and made them believe there was a killer on the loose.

Joe Alwyn says his biggest childhood prank went wrong — and involved the police.

The “Brutalist” actor shared Friday on “The Drew Barrymore Show” that, decades before he dated Taylor Swift and (and possibly became the inspiration for the title of her 2024 album, “The Tortured Poets Department,”) he tortured his entire neighborhood with a bloody practical joke.

“When I was ... about eight years old, I thought it would be a fun idea to prank the neighbors and I wrote some letters,” Alwyn told Barrymore. “They were prank-y, but they were of the threatening prank-y kind, and they were dipped in fake blood from a toy store.”

Alwyn, who grew up in a small town near London, sheepishly added, “I can’t believe I’m telling this,” before explaining how he and his older brother Thomas left the letters in every mailbox on his block.

He told Barrymore: “My parents got back from a dog walk and the phone rang and it was a neighbor on the phone to them saying, ‘Have you got one too?’ And me and my brother thought this was really funny, ’cause it was working! Success!”