Watt, 27, and Hudson, 36, are sitting next to each other at a restaurant and playing with photo filters, reported People magazine.
"Apparently the stars belong to the hottest person on the date, that's why Kate wins," Watt said in the video, while moving the camera phone from Hudson to himself.
When the "star" filter appears over Watt's head as well, the two new friends share an excited reaction and a laugh.
Hudson was most recently linked to Nick Jonas.