diff --git a/public/app/plugins/datasource/prometheus/datasource.test.ts b/public/app/plugins/datasource/prometheus/datasource.test.ts
index f3b20c84710..5a423957ff8 100644
--- a/public/app/plugins/datasource/prometheus/datasource.test.ts
+++ b/public/app/plugins/datasource/prometheus/datasource.test.ts
@@ -571,6 +571,13 @@ describe('PrometheusDatasource', () => {
   });
 
   describe('applyTemplateVariables', () => {
+    const originalAdhocFiltersMock = templateSrvStub.getAdhocFilters();
+    const originalReplaceMock = jest.fn((a: string, ...rest: any) => a);
+    afterAll(() => {
+      templateSrvStub.getAdhocFilters.mockReturnValue(originalAdhocFiltersMock);
+      templateSrvStub.replace = originalReplaceMock;
+    });
+
     it('should call replace function for legendFormat', () => {
       const query = {
         expr: 'test{job="bar"}',
@@ -608,7 +615,32 @@ describe('PrometheusDatasource', () => {
       const interpolatedQuery = ds.applyTemplateVariables(query, { interval: { text: interval, value: interval } });
       expect(interpolatedQuery.interval).not.toBe(interval);
     });
+
+    it('should add ad-hoc filters to expr', () => {
+      templateSrvStub.replace = jest.fn((a: string) => a);
+      templateSrvStub.getAdhocFilters.mockReturnValue([
+        {
+          key: 'k1',
+          operator: '=',
+          value: 'v1',
+        },
+        {
+          key: 'k2',
+          operator: '!=',
+          value: 'v2',
+        },
+      ]);
+
+      const query = {
+        expr: 'test{job="bar"}',
+        refId: 'A',
+      };
+
+      const result = ds.applyTemplateVariables(query, {});
+      expect(result).toMatchObject({ expr: 'test{job="bar",k1="v1",k2!="v2"}' });
+    });
   });
+
   describe('metricFindQuery', () => {
     beforeEach(() => {
       const query = 'query_result(topk(5,rate(http_request_duration_microseconds_count[$__interval])))';
diff --git a/public/app/plugins/datasource/prometheus/datasource.ts b/public/app/plugins/datasource/prometheus/datasource.ts
index bff676357bb..28b034dfb70 100644
--- a/public/app/plugins/datasource/prometheus/datasource.ts
+++ b/public/app/plugins/datasource/prometheus/datasource.ts
@@ -503,15 +503,7 @@ export class PrometheusDatasource extends DataSourceWithBackend<PromQuery, PromO
     let expr = target.expr;
 
     // Apply adhoc filters
-    const adhocFilters = this.templateSrv.getAdhocFilters(this.name);
-    expr = adhocFilters.reduce((acc: string, filter: { key?: any; operator?: any; value?: any }) => {
-      const { key, operator } = filter;
-      let { value } = filter;
-      if (operator === '=~' || operator === '!~') {
-        value = prometheusRegularEscape(value);
-      }
-      return addLabelToQuery(acc, key, value, operator);
-    }, expr);
+    expr = this.enhanceExprWithAdHocFilters(expr);
 
     // Only replace vars in expression after having (possibly) updated interval vars
     query.expr = this.templateSrv.replace(expr, scopedVars, this.interpolateQueryExpr);
@@ -909,6 +901,20 @@ export class PrometheusDatasource extends DataSourceWithBackend<PromQuery, PromO
     return getOriginalMetricName(labelData);
   }
 
+  enhanceExprWithAdHocFilters(expr: string) {
+    const adhocFilters = this.templateSrv.getAdhocFilters(this.name);
+    let finalQuery = expr;
+    finalQuery = adhocFilters.reduce((acc: string, filter: { key?: any; operator?: any; value?: any }) => {
+      const { key, operator } = filter;
+      let { value } = filter;
+      if (operator === '=~' || operator === '!~') {
+        value = prometheusRegularEscape(value);
+      }
+      return addLabelToQuery(acc, key, value, operator);
+    }, finalQuery);
+    return finalQuery;
+  }
+
   // Used when running queries trough backend
   filterQuery(query: PromQuery): boolean {
     if (query.hide || !query.expr) {
@@ -920,14 +926,18 @@ export class PrometheusDatasource extends DataSourceWithBackend<PromQuery, PromO
   // Used when running queries trough backend
   applyTemplateVariables(target: PromQuery, scopedVars: ScopedVars): Record<string, any> {
     const variables = cloneDeep(scopedVars);
+
     // We want to interpolate these variables on backend
     delete variables.__interval;
     delete variables.__interval_ms;
 
+    //Add ad hoc filters
+    const expr = this.enhanceExprWithAdHocFilters(target.expr);
+
     return {
       ...target,
       legendFormat: this.templateSrv.replace(target.legendFormat, variables),
-      expr: this.templateSrv.replace(target.expr, variables, this.interpolateQueryExpr),
+      expr: this.templateSrv.replace(expr, variables, this.interpolateQueryExpr),
     };
   }
 }