The video shows the Democratic presidential hopeful praising Markey as a leader, fighter and "our country's greatest champion for clean energy jobs." It comes as supporters of U.S. Rep. Joe Kennedy are pressing him to challenge Markey in next year's Democratic primary.
Markey released the 90-second video Monday. Warren had previously endorsed him.
A spokeswoman for Kennedy, grandson of Sen. Robert Kennedy, has said he appreciates the interest, but is running for re-election for the state's 4th Congressional District.
Markey is already facing two, lesser-known candidates - Shannon Liss-Riordan, a workers' rights lawyer, and Steve Pemberton, a former senior executive at Walgreens.
Kennedy was a student of Warren's at Harvard Law School.
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