The episode, titled 'The Kazanjian Brothers', will combine live-action footage with animated scenes and airs this Friday, May 15.
Production on the episode was shut down in March due to the coronavirus pandemic after it was halfway through filming in New York City.
Following the shutdown, series creator Jon Bokenkamp and producer John Eisendrath decided to use animation, taking inspiration from The Blacklist's existing comics.
The production team worked on the episode remotely while the cast provided the voiceovers from their homes.
Bokenkamp said the idea came after he joked to Eisendrath that it'd be fun to transform what they already had into "an old-school radio broadcast where we put the image of a crackling fire or a radio up on TV and the actors could voice it".
However, he added: "It's possible that if we knew how much work it took to do an animated half of this episode, we might well have not come up with the idea."
Meanwhile, the show has promoted cast member Laura Sohn to a series regular as FBI Agent Alina Park for season eight.
The larger Blacklist role will mark Sohn's first series regular job, having played a number of smaller parts in other shows.
The Blacklist season 7 finale will air on NBC on Friday, May 15. In the UK, the show airs on Sky One on Thursdays at 9pm.
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