CUT pineapple in half lengthwise, leaving leaves on. Cut out fruit, being careful not to cut all the way through each pineapple shell. Reserve shells for later use. Cut out and discard pineapple cores. Cut fruit into small pieces; place in large bowl. Add avocado; mix lightly. Set aside.
MIX cream cheese, mayo, salt and pepper until well blended. Add to pineapple mixture; mix lightly.
PAT insides of both pineapple shells dry with paper towels. Fill evenly with the pineapple mixture just before serving.