BOSTON (AP) — U.S. Sen. Ed Markey and his Democratic primary challenger, U.S. Rep. Joe Kennedy III, are planning to face off in their first televised debate. 

WGBH News will host the hour-long debate Tuesday at 7 p.m. and also will stream it online.

The race is pitting two well-known politicians against each other, with Kennedy hoping to unseat the incumbent Markey.

Markey, 73, has served in Congress for decades — first in the House and later in the Senate. The 39-year-old Kennedy, who currently represents the state's 4th Congressional District, is a member of the state's most storied political family.

As of the start of the year, Markey had more than $4.5 million in his campaign account. Kennedy had more than $5.5 million.

The contest has been overshadowed in part by the impeachment debate and the Democratic presidential primaries.

The primary is Sept. 1.

While the two Democrats share many policy positions, Kennedy has argued it's time for new leadership.

Markey has pointed to his experience in Washington and his support for the Green New Deal resolution he introduced with New York Democratic U.S. Rep. Alexandria Ocasio Cortez.

Kennedy is also helped by his family's long political history. He's the grandson of Robert F. Kennedy, who was attorney general in his brother John F. Kennedy's White House before being elected senator.