Prick potatoes in several places. Microwave on HIGH 6 to 8 minutes or until tender, turning over and rearranging after 3 minutes. Cool 5 minutes.
Cut thin slice off top of each potato. Discard tops; scoop out centres into medium bowl, leaving 1/8-inch-thick shells. Mash potato flesh. Add cream cheese product, milk, cheese and bacon; mix well. Spoon into potato shells; wrap individually in foil. Refrigerate up to 24 hours.
Heat barbecue to medium heat. Unwrap potatoes; place on barbecue grate. Grill 15 minutes or until heated through.