Update: Twitter confirms that Costolo starts as COO next week. From a Twitter spokeswoman: “He’s a long time friend of Ev and Biz, so clearly they trust and respect the work that he’s done and look forward to working with him here at Twitter HQ.”

Original: Looks like Twitter is adding some real-time experience. TechCrunch reports, citing unidentified sources, that Dick Costolo, cofounder and former CEO of FeedBurner, is headed to the startup as COO. Costolo’s no newcomer to Twitter: he was among the early investors in Twitter back in 2007. He went to Google (NSDQ: GOOG) following the company’s acquisition of FeedBurner for a reported $100 million; his profile there still lists him as a Chicago-based “software executive” at Google but he left in July. Feedburner was funded by Union Square Ventures, also an investor in Twitter, so this is the old gang reuniting.