Healey-Driscoll Administration partners with Boston Symphony Orchestra for signature Massachusetts 250 event on July 4. (Henry Shifrin/Governor’s Press Office] via Flickr, CC BY-NC-SA 4.0)

BOSTON MAYOR MICHELLE WU formally endorsed Gov. Maura Healey and Lt. Gov. Kim Driscoll for reelection Thursday morning, citing a “partnership to build a Boston and a Massachusetts that work for everyone.”

The governor and mayor, both Democrats and each the first woman elected to the chief executive positions in the state and city, are not known to have a close political connection. They backed opposing candidates in two of last month’s Democratic primaries for state Senate seats and Healey, a former Boston resident who now lives in Arlington, declined to say whether she supported Wu the day before Wu’s mayoral primary against Josh Kraft a year ago.

“I’m grateful for our work together — from a historic summer that delivered economic impact throughout our neighborhoods, to lowering costs, building more housing, keeping residents safe, and expanding opportunity throughout the Commonwealth,” Wu said in a statement provided by the Healey campaign. “I look forward to continuing to work alongside the Healey-Driscoll Administration to keep delivering results, defending our communities, and creating the future we deserve.”

Healey called Wu “such a fantastic partner and a true champion for the people of Boston” and referenced this summer’s era of good feelings around the World Cup and other popular events. “Coming off a great summer for Boston and our whole state, I’m so grateful to have worked side-by-side with her to deliver for our communities,” Healey said of Wu.

In a Tuesday social media video titled “Good luck to the Red Sox tonight!” Republican gubernatorial candidate Mike Minogue took a jab at both Healey and Wu. The short starts by showing a clip of Healey and Wu being booed on the field at Fenway Park this April and displays the message, “Looks like fans want someone else up to bat” before Minogue turns towards the camera in what appears to be a Star Trek captain’s chair.

Healey and Wu plan to be available to the press later Thursday. The pair are scheduled to celebrate new retrofits and renovations at Otis Elementary School in East Boston at 11:30 a.m.