diff --git a/rest_framework/pagination.py b/rest_framework/pagination.py
index 0f0aa9ccf..87ff7d3d6 100644
--- a/rest_framework/pagination.py
+++ b/rest_framework/pagination.py
@@ -199,8 +199,6 @@ class PageNumberPagination(BasePagination):
 
         paginator = self.django_paginator_class(queryset, page_size)
         page_number = self.get_page_number(request)
-        if page_number in self.last_page_strings:
-            page_number = paginator.num_pages
 
         try:
             self.page = paginator.page(page_number)
@@ -218,7 +216,10 @@ class PageNumberPagination(BasePagination):
         return list(self.page)
 
     def get_page_number(self, request):
-        return request.query_params.get(self.page_query_param, 1)
+        page_number = request.query_params.get(self.page_query_param, 1)
+        if page_number in self.last_page_strings:
+            page_number = paginator.num_pages
+        return page_number
 
     def get_paginated_response(self, data):
         return Response(OrderedDict([