WASHINGTON (Reuters) -A former lawyer for Donald Trump on Thursday pleaded guilty to six counts of conspiracy for aiding the former U.S. president's efforts to overturn his election defeat in the state of Georgia, a live court proceeding showed.

The lawyer, Sidney Powell, pleaded guilty to six counts of conspiracy to commit intentional interference with performance of election duties and agreed to testify against Trump and other co-defendants in the case if called upon.

Trump, the frontrunner for the 2024 Republican presidential nomination, has pleaded not guilty to a sweeping Fulton County, Georgia, indictment charging him with violating Georgia's Racketeer Influenced and Corrupt Organizations, or RICO, act in its efforts to overturn his loss to Democratic President Joe Biden.

Powell admitted to plotting to unlawfully access secure election machines in rural Coffee County in southeastern Georgia in January 2021. The plea agreement calls for her to be sentenced to six years of probation.

Powell represented Trump following the 2020 presidential election and helped spread his false claims that the election had been marred by widespread voter fraud.

(Reporting by Andrew Goudsward and Kanishka Singh; Editing by Scott Malone)