Twitter Inc said it appointed former Google executive Omid Kordestani as its executive chairman.

Twitter's shares were up 1 percent to $29.36 in early trading after the company's newly appointed chief executive, Jack Dorsey, tweeted the appointment.

Twitter had said it would look elsewhere for a chairman, seeking to allay concerns about co-founder Dorsey's dual role as head of the mobile payments company Square Inc.

Kordestani will no longer be affiliated with Google, a source familiar with the matter told Reuters.

"It's rare you get to be at a company with an amazing business that's also transforming the world," Kordestani tweeted. "I've had good fortune to be at three: Netscape, @google, and now @twitter."

Kordestani, who hold a masters degree in business administration from Stanford University, joined Google in 1999, as its 11th employee, according to his LinkedIn profile.

After 10 years of executive positions at Google, he became a senior adviser at the company in August to help it through leadership and structural changes as it rebranded itself as Alphabet Inc.

Some investors had expressed concerns about whether Dorsey could run both Twitter and Square, which he also co-founded.

Square is expected to go public this year and Dorsey may have to devote substantial time courting investors for the IPO.

Twitter said on Tuesday it would cut about 8 percent of its workforce, as Dorsey readies to revive growth in the microblogging company's user base in his second stint as CEO.

Dorsey was appointed Twitter's interim CEO in July after Dick Costolo resigned.

Google did not immediately respond to requests for comment.