Debra Lee, the first African-American to serve on Twitter's board of directors, is stepping down from the role in August after more than three years, according to a filing to the Securities and Exchange Commission on Monday.
Twitter's announcement came on the same day AT&T announced that Lee would be joining its board of directors.
"Twitter is a terrific company with a clear mission and strong leadership team," Lee said in a statement. "I believe Twitter has a bright future, and I wish Jack and the entire company continued success."
Twitter, like other tech companies, has been criticized for not having enough diversity on their board of directors. When Lee joined Twitter's board in 2016, civil rights activists praised the company's decision.
Lee is the former chairwoman and CEO of BET Networks.