Twitter co-founder Jack Dorsey will return to the micro-blogging site as executive chairman, the company confirmed Monday.
"Excited that Twitter Chairman @jack will be returning to the company day-to-day leading product as Executive Chairman," Twitter CEO Dick Costolo tweeted earlier today.
Dorsey also confirmed the move on - where else? - his Twitter feed, and said he will continue to head up his other online venture, Square.
"Today I'm thrilled to get back to work at @Twitter leading product as Executive Chairman. And yes: leading @Square forevermore as CEO. #200%," Dorsey tweeted.
Rumors about Dorsey's return to Twitter made headlines last week, when Business Insider said Dorsey would come back as a chief product officer, but Twitter and Dorsey did not confirm until today.
Dorsey co-founded Twitter with Ev Williams and Biz Stone five years ago, and served as chief executive until 2008. At that time, Williams assumed the CEO role while Dorsey served as chairman. Williams later stepped down from that role in October 2010, and Costolo took over.
Twitter recently celebrated its fifth birthday, and Dorsey summarized the company's history in a series of 140-character tweets. Stone also appeared on Conan O'Brien's show, where he was mocked, and thanked, by the host for Twitter's efforts.
In December 2009, Dorsey announced Square, a mobile payment system that enables credit card transactions by phone. The company formally launched for iOS and Android devices in May 2010, allowing street vendors and other users to accept credit-card payments on the go.
Mobile payment systems have been slow to catch on, but there have recently been a variety of stories about the technology as more and more companies examine near-field communication (NFC), including Research in Motion, Google and Apple.