If you’re looking to boost your share of holiday customers at the last moment, Facebook and Instagram have a new feature that will be of interest to you.

The companies are rolling out a new ad-targeting segment aimed at helping brands focus in on shoppers who are engaged with content related to holiday shopping, including Black Friday and Cyber Monday. The ad segments, which will run from Thanksgiving to New Year’s Day, act like any other ad format on their advertising networks.

Facebook says it will compile this audience by watching for holiday-related keywords in posts that people publish, like, comment on, and share. From there, the audience is aggregated and anonymized, like all Facebook ad-segments.

The holiday ad segment is available now within Facebook self-service ad dashboards, in the “Behaviors” section under the “Seasonal and Events” category.