Lingerie-clad Lily Allen shows ex David Harbour what he’s missing after Halloween costume jab

That’s a big “F–k You.”

Lily Allen wore lingerie under her shady Halloween costume on Friday to show her estranged husband, David Harbour, what he’s missing.

The “Smile” singer turned up the heat while dressed as the beloved children’s book character, Madeline, at Vas J Morgan and Michael Braun’s star-studded Halloween party at Chateau Marmont in Los Angeles.

Allen channeled the famous illustrations by Ludwig Bemelmans in a short blue coat with a red tie, a boater hat, ankle socks, black Mary Janes and a short orange wig.

However, she stripped down to a barely-there lingerie look once inside the exclusive bash.

The pop star posed for a sultry snap in a lacy white onesie paired with frilly blue underwear, in a photo posted to her Instagram Sunday.

She shared another image of herself wearing sheer black lingerie with a black skirt at another event.

“West End Girl In a West Hollywood World,” Allen captioned the social media roundup, referring to the title of her “West End Girl” album released last week.

She also shared a TikTok video of herself smoking a vape in her cheeky Madeline costume, captioning the video, “Who IS Madeline though, actually?”

Allen used her Madeline ensemble to throw shade at Harbour after suggesting that he cheated on her in the fifth song on her album, “Madeline.”

In the scathing lyrics, Allen hints at Harbour’s alleged affair by having a conversation with a woman whom she believes to be his mistress, asking, “How long has it been going on? Is it just sex or is there emotion?”

Allen continued to allude to Harbour’s alleged infidelity in other tracks.

In “Dallas Major,” she sings about a relationship being “open” when her partner “went astray,” breaking down her ex’s “double life” in “P–sy Palace.”

Allen released her viral new music after she and Harbour, who wed in 2020, separated in February after four years together.

Following the emotional examination of her and Harbour’s relationship, rumors swirled that the “Stranger Things” star cheated on Allen with costume designer Natalie Tippett.