Lily Allen makes savage dig at ex David Harbour’s mistress with ‘Madeline’ Halloween costume

Trick or treat.

Lily Allen made another savage dig at her estranged husband, David Harbour, by dressing up as the mistress she named in her song “Madeline” for Halloween 2025.

On Friday, the “Smile” singer took to TikTok to share a video of herself dressed as Madeline from the beloved children’s book series.

In a clip set to the tune of Cardi B’s “Magnet,” Allen — who was dressed in a blue collared pea coat with a red neckerchief, a straw hat, Mary Jane shoes and a bright orange wig — pranced down a hallway while looking directly at the camera.

At one point, the British singer, 40, took a hit of her neon green vape before turning around and dancing back up the hallway.

“Who IS Madeline though, actually?” she captioned the post.

Fans took to Allen’s TikTok comments section to share their thoughts on the singer’s latest shady move.

“PERFECT NO NOTES,” wrote one user.

“The crashout is so valid,” added another.

“you had the opportunity to do the funniest thing and you did 😂,” commented a third person.

“I thought to myself ‘🤔 let’s see how Lily’s Halloween is going.’ Love to see it 👏👏👏,” said a fourth netizen.

Page Six has reached out to Harbour’s rep for comment but did not immediately hear back.

In February, news broke that Allen and the “Stranger Things” actor, 50, were divorcing after four years of marriage. The “Hard Out Here” singer then revealed that she had gone to a treatment center for “emotional turmoil.”

Allen filed for divorce last month.

The pop star shared details about Harbour’s alleged infidelity on her newly released album, “West End Girl.”

On the song “Madeline,” Allen sang about Harbour breaking the rules in their “open” marriage.

The other woman was later revealed to be Natalie Tippett, a costume designer who allegedly began an affair with Harbour while they worked together on a 2021 Netflix film.

A day after the album was released, Harbour brushed off the drama by taking Allen’s daughters, Ethel Mary, 13, and Marnie Rose, 12, to Universal Epic Universe in Orlando, Fla., for a day of fun.