Despite numerous denials by Carell himself, The Office U.S. creator Greg Daniels, various cast members and an NBC exec, TVLine is reporting that Steve Carell WILL be returning for a cameo appearance as Michael Scott in next week's Finale episode of the Office. 

So this wasn't the last time we'll see him :)

"According to sources, Carell’s return engagement qualifies as more of a cameo than a full-fledged guest appearance. (It’s unclear if Carell will be joined by his Office soul mate Amy Ryan [Holly].)"

Thus far, The Office-isms has found TVLine's reporting of show news accurate and reliable so we have no reason to doubt it's credibility.  

Welcome back, Mr. Scott-er, welcome back, welcome back, welcome back!