It’s official. Twitter last night finalized a deal to buy TweetDeck, ending weeks of speculation.

The two companies announced the acquisition Wednesday in separate blog posts. Terms of the deal weren’t disclosed.

CNN.com reported Tuesday that Twitter was buying the maker of applications for the microblogging site for $40 million in cash and stock.

“This acquisition is an important step forward for us,” wrote Twitter CEO Dick Costolo in a blog post. “TweetDeck provides brands, publishers, marketers and others with a powerful platform to track all the real-time conversations they care about. In order to support this important constituency, we will continue to invest in the TweetDeck that users know and love.”

Iain Dodsworth, TweetDeck Founder and CEO, insinuated in his blog post that TweetDeck staff won’t be let go because of the acquisition.

“We’ve grown from one team member and a single user, to a team of 15 and a user-base of millions,” he wrote. “Change may well be inevitable, but we remain the same team, staying in London, with the same focus and products, and now with the support and resources to allow us to grow and take on even bigger challenges.”

Today’s news comes after weeks of speculation about potential future owners of TweetDeck.