Allen wore a high-neck floral-patterned dress featuring three-quarter sleeves and a pink ribbon around the neckline. She finished the look in black boots and a pair of hoop earrings, with her hair tied half-up.
Harbour — who previously dated Fantastic Beasts star Alison Sudol — and the “Not Fair” hitmaker first sparked dating rumors in January, when they attended the BAFTA Tea Party together.
They were spotted together this past August while he was filming Black Widow in London, where they attended the performance of The Lehman Trilogy at the Piccadilly Theater and then dined at a restaurant, according to E! News.
Allen shared photos from Harbour’s SNL sketch parodying a SoulCycle class, during which the host wore a sleeveless shirt and showed off his muscular arms. Allen captioned a zoomed-in photo of Harbour’s bicep, “Mine.”
The duo was then snapped locking lips as they walked through the streets of New York City the next day to grab lunch together.
She was previously married to builder and decorator Sam Cooper. They married in 2011 and announced their split in 2016 before finalizing their divorce last June. Allen and Cooper, 41, share two daughters: Marnie Rose, 6½, and Ethel Mary, 8 next month.
In her latest Instagram post last week, Allen proclaimed she was “Leaving UK till after Brexit. Good Luck Kids.”