A portrait of the Twitter logo in Ventura, California December 21, 2013. REUTERS/Eric Thayer

(Reuters) - Twitter Inc named American Express Co executive Leslie Berland as its chief marketing officer, Chief Executive Jack Dorsey tweeted on Tuesday.

"Welcoming @leslieberland to Twitter! She will join as our CMO to help tell the stories of our iconic product!," Dorsey tweeted. (bit.ly/20qySZo)

Berland, who joined AmEx in 2005 and is currently executive vice president of global advertising, marketing and digital partnerships at American Express, confirmed her new job via a tweet.

Twitter Chief Operating Officer Adam Bain sent a series of tweets on Berland.

"In my role, I get to talk to the best and brightest in mktg. So when we originally drafted our dream list of CMOs, @leslieberland was #1," Bain tweeted. (bit.ly/1ZQ2HAf)

The new appointment comes after four top executives left Twitter.

Media head Katie Jacobs Stanton, product head Kevin Weil, the head of the engineering division, Alex Roetter, and HR head Brian “Skip” Schipper left the company, Dorsey tweeted late Sunday night.

Shares of the company were down 1.9 percent in morning trade on the New York Stock Exchange.