Elon Musk and Twitter CEO Linda Giaccarino today unveiled a logo for the social networking site that features a white “X” on a black background in place of the familiar blue bird symbol. “The X is here: Let’s do it,” tweeted Giaccarino, who also posted a photo of the logo on display at the company’s San Francisco offices.

Giaccarino and Musk’s accounts carry the X logo, although Twitter’s blue bird still appears on the platform.

The hashtag “#GoodbyeTwitter” (Bye, Twitter) flooded the platform with a reference to the old logo as several users criticized the new one. Musk said in a post on Sunday that he wanted to change Twitter’s logo and polled his millions of followers on the social network if they would like the site’s color to change from blue to black.

He posted a photo of a stylized X on a black background. He also spoke of a “temporary X logo” and tweeted that “soon we’ll be saying goodbye to the Twitter brand and, gradually, to all birds.” In response to a tweet asking what the “tweets” with the new “X” logo would be called, Musk replied “x’s.” The original Twitter logo was designed in 2012 by a team of three. “The logo was designed to be simple, balanced and legible in very small sizes, like an ‘e,'” Martin Grasser, one of the designers, wrote in a tweet.

A few weeks before completing the acquisition of Twitter last year, Musk said buying the company would accelerate his ambition to create an “app for everything” under the “X” brand by three to five years.

Musk bought x.com from PayPal in 2017, saying it has “sentimental value.” Musk co-founded x.com as an online bank in 1999 that later became PayPal.

Although the official Twitter page on the platform has been renamed to “X,” the domain x.com has not been activated.

“X is the future state of unlimited interactivity — focused on audio, video, messaging, payments/banking — creating a global marketplace for ideas, goods, services and opportunities,” Giaccarino tweeted yesterday.

Giaccarino, the former head of advertising at NBCUniversal, who started working as CEO at Twitter on June 5, takes over as the social network tries to reverse a plunge in advertising revenue.

After acquiring Twitter, the company faced tumultuous times, with layoffs, a sharp decline in advertisers, and the meteoric rise of Threads, Meta’s answer to Twitter.