Lucille is a familiar name for fans of The Walking Dead – it's the name Negan (Jeffrey Dean Morgan) gives to his deadly baseball bat. But it was also the name of his dead wife. And now, Lucille – the character, not the bat – has been cast in the series, with Hilarie Burton set to play the part. This is interesting for multiple reasons. One is that Lucille is dead, which means her addition implying flashbacks. The other is that despite being mentioned in the core comics, the character herself is never seen.
THR and others are reporting that Hilarie Burton will play Negan's wife Lucille, who will "appear in the upcoming batch of season 10 bonus episodes." You can expect her appearence to either be part of a flashback or a dream sequence, since Lucille is dead. Here's more info on the character from the Walking Dead Wiki:
Not much is known about Lucille's life prior to or as the outbreak began, except that she was married to Negan, they lived together in Virginia and she was suffering from pancreatic cancer shortly before the outbreak. Lucille underwent chemotherapy which caused Lucille to lose her hair and was causing her to become sick. Additionally, she was actively being cheated on by Negan. After she died and reanimated, Negan couldn't bring himself to put Lucille down, which he came to see as his one weakness. Negan evidently dedicated his signature weapon, a wooden baseball bat wrapped in barbed wire, after her.
As I mentioned above, the character has only been mentioned and never seen in the main Walking Dead comic (she is a minor character in a series of short comics published in the Image+ magazine), so Burton will have some freedom to do whatever she wants with the character and not have to worry too much about clinging to the source material. And course, it's worth noting that Burton just happens to be married to Negan actor Jeffrey Dean Morgan..
"Been pretty hard to keep this a secret. But I love working with Jeffrey Dean Morgan. I love watching him become Negan and take on that swagger. And I love the The Walking Dead family," Burton wrote on Twitter. "They've been a part of our family for ages and I'm so grateful for their kindness."