diff --git a/packages/common/http/src/client.ts b/packages/common/http/src/client.ts
index 77c82fe4db..896974ddb1 100644
--- a/packages/common/http/src/client.ts
+++ b/packages/common/http/src/client.ts
@@ -15,7 +15,7 @@ import {map} from 'rxjs/operator/map';
 
 import {HttpHandler} from './backend';
 import {HttpHeaders} from './headers';
-import {HttpParams} from './params';
+import {HttpParams, HttpParamsOptions} from './params';
 import {HttpRequest} from './request';
 import {HttpEvent, HttpResponse} from './response';
 
@@ -364,7 +364,7 @@ export class HttpClient {
         if (options.params instanceof HttpParams) {
           params = options.params;
         } else {
-          params = new HttpParams({fromObject: options.params});
+          params = new HttpParams({ fromObject: options.params } as HttpParamsOptions);
         }
       }
 
diff --git a/packages/common/http/src/params.ts b/packages/common/http/src/params.ts
index 555f45efd2..170f151fe6 100755
--- a/packages/common/http/src/params.ts
+++ b/packages/common/http/src/params.ts
@@ -73,6 +73,21 @@ interface Update {
   op: 'a'|'d'|'s';
 }
 
+/** Options used to construct an `HttpParams` instance. */
+export interface HttpParamsOptions {
+  /**
+   * String representation of the HTTP params in URL-query-string format. Mutually exclusive with
+   * `fromObject`.
+   */
+  fromString?: string;
+
+  /** Object map of the HTTP params. Mutally exclusive with `fromString`. */
+  fromObject?: {[param: string]: string | string[]};
+
+  /** Encoding codec used to parse and serialize the params. */
+  encoder?: HttpParameterCodec;
+}
+
 /**
  * An HTTP request/response body that represents serialized parameters,
  * per the MIME type `application/x-www-form-urlencoded`.
@@ -87,19 +102,7 @@ export class HttpParams {
   private updates: Update[]|null = null;
   private cloneFrom: HttpParams|null = null;
 
-  constructor(options = {} as {
-    /**
-     * String representation of the HTTP params in URL-query-string format. Mutually exclusive with
-     * `fromObject`.
-     */
-    fromString?: string;
-
-    /** Object map of the HTTP params. Mutally exclusive with `fromString`. */
-    fromObject?: {[param: string]: string | string[]};
-
-    /** Encoding codec used to parse and serialize the params. */
-    encoder?: HttpParameterCodec;
-  }) {
+  constructor(options: HttpParamsOptions = {} as HttpParamsOptions) {
     this.encoder = options.encoder || new HttpUrlEncodingCodec();
     if (!!options.fromString) {
       if (!!options.fromObject) {
@@ -183,7 +186,7 @@ export class HttpParams {
   }
 
   private clone(update: Update): HttpParams {
-    const clone = new HttpParams({encoder: this.encoder});
+    const clone = new HttpParams({ encoder: this.encoder } as HttpParamsOptions);
     clone.cloneFrom = this.cloneFrom || this;
     clone.updates = (this.updates || []).concat([update]);
     return clone;
diff --git a/tools/public_api_guard/common/http.d.ts b/tools/public_api_guard/common/http.d.ts
index d341eadb45..fd066926af 100644
--- a/tools/public_api_guard/common/http.d.ts
+++ b/tools/public_api_guard/common/http.d.ts
@@ -1580,13 +1580,7 @@ export interface HttpParameterCodec {
 
 /** @stable */
 export declare class HttpParams {
-    constructor(options?: {
-        fromString?: string | undefined;
-        fromObject?: {
-            [param: string]: string | string[];
-        } | undefined;
-        encoder?: HttpParameterCodec | undefined;
-    });
+    constructor(options?: HttpParamsOptions);
     append(param: string, value: string): HttpParams;
     delete(param: string, value?: string): HttpParams;
     get(param: string): string | null;