Midjourneyが占星術アプリCo-Starを買収Midjourney bought the astrology app Co-Star

Midjourney, the AI image-generation company best known for producing photorealistic and stylized art from text prompts, has acquired Co-Star, the popular astrology app with a devoted following among younger smartphone users. The pairing is unusual enough to raise immediate questions, and it appears to signal Midjourney's intent to move beyond visual generation into personality-driven, personal-data-rich consumer experiences.

Co-Star built its reputation on a distinctive aesthetic and a data-heavy approach to horoscopes. The app pulls real-time planetary positions, historically drawing on NASA ephemeris data, and combines them with a user's birth date, time, and location to generate a natal chart. Its notifications, often blunt and occasionally unsettling in tone, became a cultural signature and helped the app spread through social media. For readers unfamiliar with the terminology, a natal chart is a map of where the planets sat at the moment of a person's birth, which astrology practitioners use as the basis for individualized readings. That means Co-Star holds a trove of granular personal information, including precise birth details and behavioral data about how users engage with daily prompts.

That data appears to be central to the logic of the deal. Midjourney has spent the past two years expanding its ambitions well beyond still images, including work on video generation and its own web platform, as it seeks to reduce reliance on the Discord interface that originally defined the service. Acquiring a consumer app with an established user base, a recognizable brand, and a steady stream of first-party personal data gives Midjourney a foothold in a category that is fundamentally about generating personalized content for individuals. Astrology content, which is subjective and open-ended, is also relatively forgiving territory for generative systems, since users do not expect factual precision the way they might from a search engine or a coding assistant.

Neither company has detailed exactly how Co-Star will change, but the combination is likely to point toward AI-generated readings, imagery, and possibly interactive features tailored to each user's chart. Midjourney's core strength is producing visuals, and it is reasonable to expect the astrology experience could become more image-forward, blending generated art with the text-based guidance Co-Star already offers. Whether the underlying astrological logic remains rule-based or shifts toward large language model output is not yet clear.

The acquisition arrives amid a broader wave of consolidation in which AI developers are buying consumer-facing products to gain distribution, brand recognition, and, crucially, proprietary data to differentiate their models. Training and personalization increasingly depend on access to real user interactions, and off-the-shelf datasets are less useful for building distinctive experiences. Owning an app also gives an AI company a direct relationship with paying users, something Midjourney has cultivated through subscriptions but which astrology apps have monetized through their own premium tiers and add-ons.

The move also invites scrutiny over privacy. Combining an image-generation company with a service that stores intimate personal details, including exact birth times and, in some cases, relationship and social data, raises questions about how that information might be used, retained, or fed into model development. Co-Star users may reasonably want clarity on whether their data could inform Midjourney's broader systems, and regulators in some jurisdictions have grown more attentive to how AI firms handle personal information gathered through acquisitions. As of now, the companies have not published specifics about data governance under the new ownership.

For context, Midjourney has operated as a relatively small, self-funded organization compared with rivals such as OpenAI, Google, and Stability AI, and it has generally avoided the acquisition-heavy strategies of larger competitors. That makes this purchase notable as a departure, suggesting the company sees consumer products, rather than pure model development, as a path to growth. Co-Star, for its part, had faced the challenge many viral apps encounter: sustaining engagement and revenue after an initial surge in popularity.

The deal ultimately reflects a wider industry bet that generative AI's next phase will be less about one-off outputs and more about persistent, personalized companions built on individual data. Whether astrology proves to be a durable vehicle for that vision, or simply an unexpected experiment, remains to be seen.