USAF hasn't solidified a final date but announced the unveiling event would take place at Northrop's facilities in Palmdale, California.
"We are still working to nail down all the plans," Air Force acquisition executive Andrew Hunter said during a discussion with reporters at the Air Force Association's Air, Space, and Cyber conference, on Tuesday.
Northrop disclosed that it has six B-21s in "various stages of final assembly" at the Palmdale facility, with the first flight scheduled for 2023.
"The B-21 is the most advanced military aircraft ever built and is a product of pioneering innovation and technological excellence.
"The Raider showcases the dedication and skills of the thousands of people working every day to deliver this aircraft," said Doug Young, sector vice president and general manager, Northrop Grumman Aeronautics Systems.
December's event will be the first time in 34 years Northrop has unveiled a stealth bomber. In 1988, Northrop gave the first public display of the B-2 bomber that flew the following year and was introduced into service in 1997.
"Northrop Grumman is proud of our partnership with the US Air Force as we deliver the B-21 Raider, a sixth-generation aircraft optimized for operations in highly contested environments," said Tom Jones, corporate vice president and president, Northrop Grumman Aeronautics Systems.
Northrop has been preparing to unveil the B-21 well before the war in Ukraine. China and Russia have also revealed renderings of stealth bombers, but the US could beat them to the skies. As far as hypersonic missiles, that's a different story...
When the B-21s are ready for service, Whiteman Air Force Base in Missouri will be their new home.