diff --git a/modules/appnexusBidAdapter.js b/modules/appnexusBidAdapter.js
index 5210d6f7562..bb80b6a8588 100644
--- a/modules/appnexusBidAdapter.js
+++ b/modules/appnexusBidAdapter.js
@@ -774,6 +774,18 @@ function bidToTag(bid) {
   } else {
     tag.code = bid.params.inv_code;
   }
+  // Xandr expects GET variable to be in a following format:
+  // page.html?ast_override_div=divId:creativeId,divId2:creativeId2
+  const overrides = getParameterByName('ast_override_div');
+  if (isStr(overrides) && overrides !== '') {
+    const adUnitOverride = overrides.split(',').find((pair) => pair.startsWith(`${bid.adUnitCode}:`));
+    if (adUnitOverride) {
+      const forceCreativeId = adUnitOverride.split(':')[1];
+      if (forceCreativeId) {
+        tag.force_creative_id = parseInt(forceCreativeId, 10);
+      }
+    }
+  }
   tag.allow_smaller_sizes = bid.params.allow_smaller_sizes || false;
   tag.use_pmt_rule = (typeof bid.params.use_payment_rule === 'boolean') ? bid.params.use_payment_rule
     : (typeof bid.params.use_pmt_rule === 'boolean') ? bid.params.use_pmt_rule : false;
diff --git a/test/spec/modules/appnexusBidAdapter_spec.js b/test/spec/modules/appnexusBidAdapter_spec.js
index cc86a8a0aaa..2a277cf1ba7 100644
--- a/test/spec/modules/appnexusBidAdapter_spec.js
+++ b/test/spec/modules/appnexusBidAdapter_spec.js
@@ -1442,6 +1442,88 @@ describe('AppNexusAdapter', function () {
       config.getConfig.restore();
     });
 
+    describe('ast_override_div', function () {
+      let getParamStub;
+      let bidRequest = Object.assign({}, bidRequests[0]);
+      let bidRequest2 = deepClone(bidRequests[0]);
+      bidRequest2.adUnitCode = 'adUnit_code_2';
+      let bidRequest3 = deepClone(bidRequests[0]);
+      bidRequest3.adUnitCode = 'adUnit_code_3';
+
+      before(function () {
+        getParamStub = sinon.stub(utils, 'getParameterByName');
+      });
+
+      it('should set forced creative id if one adUnitCode passed', function () {
+        getParamStub.callsFake(function(par) {
+          if (par === 'ast_override_div') return 'adunit-code:1234';
+          return '';
+        });
+
+        const request = spec.buildRequests([bidRequest, bidRequest2]);
+        const payload = JSON.parse(request.data);
+
+        expect(payload.tags[0].force_creative_id).to.deep.equal(1234);
+        expect(payload.tags[1].force_creative_id).to.not.exist;
+      });
+
+      it('should set forced creative id if `ast_override_div` is set to override multiple adUnitCode', function () {
+        getParamStub.callsFake(function(par) {
+          if (par === 'ast_override_div') return 'adunit-code:1234,adUnit_code_2:5678';
+          return '';
+        });
+
+        const request = spec.buildRequests([bidRequest, bidRequest2, bidRequest3]);
+        const payload = JSON.parse(request.data);
+
+        expect(payload.tags[0].force_creative_id).to.deep.equal(1234);
+        expect(payload.tags[1].force_creative_id).to.deep.equal(5678);
+        expect(payload.tags[2].force_creative_id).to.not.exist;
+      });
+
+      it('should not set forced creative id if `ast_override_div` is missing creativeId', function () {
+        getParamStub.callsFake(function(par) {
+          if (par === 'ast_override_div') return 'adunit-code';
+          return '';
+        });
+
+        const request = spec.buildRequests([bidRequest, bidRequest2]);
+        const payload = JSON.parse(request.data);
+
+        expect(payload.tags[0].force_creative_id).to.not.exist;
+        expect(payload.tags[1].force_creative_id).to.not.exist;
+      });
+
+      it('should not set forced creative id if `ast_override_div` is in the wrong format', function () {
+        getParamStub.callsFake(function(par) {
+          if (par === 'ast_override_div') return 'adunit-code;adUnit_code_2:5678';
+          return '';
+        }); ;
+
+        const request = spec.buildRequests([bidRequest, bidRequest2]);
+        const payload = JSON.parse(request.data);
+
+        expect(payload.tags[0].force_creative_id).to.not.exist;
+        expect(payload.tags[1].force_creative_id).to.not.exist;
+      });
+
+      it('should not set forced creative id if `ast_override_div` is missing', function () {
+        getParamStub.callsFake(function(par) {
+          return '';
+        }); ;
+
+        const request = spec.buildRequests([bidRequest, bidRequest2]);
+        const payload = JSON.parse(request.data);
+
+        expect(payload.tags[0].force_creative_id).to.not.exist;
+        expect(payload.tags[1].force_creative_id).to.not.exist;
+      });
+
+      after(function () {
+        getParamStub.restore();
+      });
+    });
+
     it('should set the X-Is-Test customHeader if test flag is enabled', function () {
       let bidRequest = Object.assign({}, bidRequests[0]);
       sinon.stub(config, 'getConfig')