Twitter has talked to Bieber-backed Shots: Source

Who's Twitter's target now?
What's Twitter's target now?   

Twitter has held talks with Shots, the selfie app backed by singer Justin Bieber, a source close to Shots told CNBC on Tuesday.

Twitter's acquisition plans became the subject of hot speculation on Monday after CFO Anthony Noto accidentally tweeted a message about making plans for a deal.

Re/code listed a handful of potential targets, including Shots, earlier Tuesday.

Twitter is attracted particularly to Shots' user base, the source said—more than 3 million users, nearly two-thirds of them women under 24.

Pop star Bieber is an investor in the app. The company is run by John Shahidi, known to some as the "King of Twitter" for his broad popularity on the social media service.

Twitter shares fell 1 percent Tuesday, and were little changed after market close.