Peaky Blinders star adds fuel to the theory that they could be the traitor in the Shelby family
The mystery that has fans hooked.
As always, if you're not up to date with the most recent episodes of Peaky Blinders, consider this to be your spoiler alert warning.
Seriously, look away now.
Who is the 'black cat' that Tommy's convinced will betray him?
That's the main question that Peaky Binders fans are mulling over as Season 5 develops because there's no denying that there's a leak in the Shelby family.
After all, Oswald Mosley knew that Linda was spending time with another man. He also knew where Michael was spending the majority of his time in New York.
Aside from this, the most fatal leak saw the Billy Boys track down the whereabouts of Aberama Gold and his son, Bonnie. Sadly, the young boxer was crucified as the razor gang from Glasgow made an immediate impression.
Only a few people knew this information and while Tommy has plenty of enemies, the main contenders in this macabre version of Guess Who?: Peaky Blinders Edition seem to be Esme and Aunt Polly - we've outlined our reasons here and here respectively.
Esme still blames Tommy for the death of her husband, John Shelby. It's also worth remembering that she was formerly a member of the Lee clan and as we've seen, the Lees have plenty of bad blood with the Golds.
Esme was also frequently against Tommy's plans to expand into London because she wanted a quieter life with her husband. Tommy's actions also got her arrested during the Season 3 finale and after seeing John's body at the morgue, she cursed the Shelby men.
During a recent interview with Cosmopolitan, Aimee-Ffion Edwards (Esme) was asked about a potential return to Peaky Blinders and the actress was upbeat about the idea.
"It depends on the script. I feel like I got to do some really good stuff, and the storylines were really strong, and I could make the best of Esme. I think there's an element of feeling quite protective over the characters you play, and if you feel like you aren't doing that character justice... It's such a brilliant show, and such an amazing following.
"It's really exciting to be a part of but I think if the storyline was good, I would consider that but I'm quite satisfied with what I got to do with her. I'm open-minded but sometimes it's nice to leave on a high," she said.
The actress also mentioned the interesting dynamic between the Shelby family and the Lees as an area that she's potentially interested in exploring, should she return.
"The relationship between the Lees and the Shelbys is such an interesting one, and she's got plenty of kids, she has an army of kids hasn't she, so I'm sure we'll see them again at some point!," she said.
The mystery unravels when the next episode of Peaky Blinders airs this Sunday at 21:00 on BBC1.