Katie Holmes was snapped cracking a rare smile as she visited Tom Cruise on the Boston set of his new movie Wichita yesterday.

The actress – whose default expression seems to be 'glum' these days – seemed in good spirits as she let an assistant carry daughter Suri for a change.

Meanwhile, onlookers describe Tom and Katie as looking "genuinely happy together" at the U2 show in the city on Saturday.

“They were having the best time dancing, holding hands together in the air and looked genuinely happy together,” an eyewitness tells the Boston Herald.

“Cameron Diaz was dancing the entire time, turning around to laugh and smile at Tom and Katie. And when Bono asked the crowd to take out their cellphones to create light, even Cameron took out her BlackBerry.”