While their characters Dotty Cotton (Zero) and Tiffany Butcher (Smith) may be mortal frenemies, the two actors are good friends.
In a recent post to her Instagram stories, Zero shared a snap of them on set, captioning it: "Work won't be the same without you, you will be so missed."
"But go spread your wings, the world ain't ready," she added.
Watch: Eastenders spoilers
Zero signed off the post with "#NFI", which fans of the BBC One soap will know stands for "Not Flippin' Invited" a somewhat iconic comeback that Tiff has used on Dotty multiple times on the series.
Confirming her exit last week, Smith wrote in a statement: “It's time to say farewell to Tiff.
"I've grown up on EastEnders since 2008, and have learnt from the best over the past 13 years.
"I'm very excited for my next challenge and thank the BBC for the opportunity they gave me as a 6-year-old."
The star filmed her last scenes last week but will still appear in her role till the end of the year.
As for what will lead to Tiff’s departure from Albert Square, EastEnders heads are keeping details of her storyline under wraps.
However, in recent weeks her husband Keegan Baker engaged in an affair with Dotty, worsening the two women's rivalry, which could escalate with dramatic consequences.
The return of Tiff’s brother Liam is also bringing about suspicion that it doesn’t look like he is back with the best of intentions.
The soap’s executive producer Jon Sen has confirmed he remains open to seeing Smith return, so Tiff might be leaving while still holding on to her life.
EastEnders airs on Mondays, Tuesdays, Thursdays and Fridays on BBC One.
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