Former Gov. Michael Dukakis and Kitty Dukakis are backing Sen. Edward Markey in his primary contest against Rep. Joseph Kennedy III.

The former three-term governor and 1988 Democratic presidential nominee released an endorsement video on Tuesday, crediting Markey's work over the years on energy innovation and climate change.

Markey described them as the "true founders of the grassroots movement" and said he was grateful for their support. "Michael and Kitty Dukakis are the embodiment of the bold, progressive values that have made the Democratic party what it is today," Markey said.