diff --git a/src/third-party/EnsController.ts b/src/third-party/EnsController.ts
index f7d8fa14227..be0b17971fd 100644
--- a/src/third-party/EnsController.ts
+++ b/src/third-party/EnsController.ts
@@ -11,7 +11,7 @@ import { isValidAddress, toChecksumAddress } from 'ethereumjs-util';
  * @property address - Hex address with the ENS name
  */
 export interface EnsEntry {
-	chainId: number;
+	chainId: string;
 	ensName: string;
 	address: string;
 }
@@ -27,17 +27,6 @@ export interface EnsState extends BaseState {
 	ensEntries: { [chainId: string]: { [ensName: string]: EnsEntry } };
 }
 
-/**
- * @type EnsEntriesState
- *
- * ENS controller state
- *
- * @property ensEntries - Object of ENS entry objects
- */
-interface EnsEntriesState {
-	[chainId: string]: { [ensName: string]: EnsEntry };
-}
-
 /**
  * Controller that manages a list ENS names and their resolved addresses
  * by chainId
@@ -75,12 +64,12 @@ export class EnsController extends BaseController<BaseConfig, EnsState> {
 	 * @param chainId - Parent chain of the ENS entry to delete
 	 * @param ensName - Name of the ENS entry to delete
 	 */
-	delete(chainId: number, ensName: string) {
+	delete(chainId: string, ensName: string) {
 		if (!this.state.ensEntries[chainId] || !this.state.ensEntries[chainId][ensName]) {
 			return false;
 		}
 
-		const ensEntries: EnsEntriesState = Object.assign({}, this.state.ensEntries);
+		const ensEntries = Object.assign({}, this.state.ensEntries);
 		delete ensEntries[chainId][ensName];
 
 		if (Object.keys(ensEntries[chainId]).length === 0) {
@@ -99,8 +88,13 @@ export class EnsController extends BaseController<BaseConfig, EnsState> {
 	 * @param address - Associated address to add or update
 	 * @returns - Boolean indicating whether the entry was set
 	 */
-	set(chainId: number, ensName: string, address: string): boolean {
-		if (!Number.isInteger(chainId) || !ensName || typeof ensName !== 'string' || !isValidAddress(address)) {
+	set(chainId: string, ensName: string, address: string): boolean {
+		if (
+			!Number.isInteger(Number.parseInt(chainId, 10)) ||
+			!ensName ||
+			typeof ensName !== 'string' ||
+			!isValidAddress(address)
+		) {
 			throw new Error(`Invalid ENS entry: { chainId:${chainId}, ensName:${ensName}, address:${address}}`);
 		}
 
diff --git a/tests/EnsController.test.ts b/tests/EnsController.test.ts
index f8f54cab6c9..e8e95547f63 100644
--- a/tests/EnsController.test.ts
+++ b/tests/EnsController.test.ts
@@ -20,13 +20,13 @@ describe('EnsController', () => {
 
 	it('should add a new ENS entry and return true', () => {
 		const controller = new EnsController();
-		expect(controller.set(1, name1, address1)).toBeTruthy();
+		expect(controller.set('1', name1, address1)).toBeTruthy();
 		expect(controller.state).toEqual({
 			ensEntries: {
 				1: {
 					[name1]: {
 						address: address1Checksum,
-						chainId: 1,
+						chainId: '1',
 						ensName: name1
 					}
 				}
@@ -36,14 +36,14 @@ describe('EnsController', () => {
 
 	it('should update an ENS entry and return true', () => {
 		const controller = new EnsController();
-		expect(controller.set(1, name1, address1)).toBeTruthy();
-		expect(controller.set(1, name1, address2)).toBeTruthy();
+		expect(controller.set('1', name1, address1)).toBeTruthy();
+		expect(controller.set('1', name1, address2)).toBeTruthy();
 		expect(controller.state).toEqual({
 			ensEntries: {
 				1: {
 					[name1]: {
 						address: address2Checksum,
-						chainId: 1,
+						chainId: '1',
 						ensName: name1
 					}
 				}
@@ -53,14 +53,14 @@ describe('EnsController', () => {
 
 	it('should not update an ENS entry if the address is the same and return false', () => {
 		const controller = new EnsController();
-		expect(controller.set(1, name1, address1)).toBeTruthy();
-		expect(controller.set(1, name1, address1)).toBeFalsy();
+		expect(controller.set('1', name1, address1)).toBeTruthy();
+		expect(controller.set('1', name1, address1)).toBeFalsy();
 		expect(controller.state).toEqual({
 			ensEntries: {
 				1: {
 					[name1]: {
 						address: address1Checksum,
-						chainId: 1,
+						chainId: '1',
 						ensName: name1
 					}
 				}
@@ -70,28 +70,28 @@ describe('EnsController', () => {
 
 	it('should add multiple ENS entries and update without side effects', () => {
 		const controller = new EnsController();
-		expect(controller.set(1, name1, address1)).toBeTruthy();
-		expect(controller.set(1, name2, address2)).toBeTruthy();
-		expect(controller.set(2, name1, address1)).toBeTruthy();
-		expect(controller.set(1, name1, address3)).toBeTruthy();
+		expect(controller.set('1', name1, address1)).toBeTruthy();
+		expect(controller.set('1', name2, address2)).toBeTruthy();
+		expect(controller.set('2', name1, address1)).toBeTruthy();
+		expect(controller.set('1', name1, address3)).toBeTruthy();
 		expect(controller.state).toEqual({
 			ensEntries: {
 				1: {
 					[name1]: {
 						address: address3Checksum,
-						chainId: 1,
+						chainId: '1',
 						ensName: name1
 					},
 					[name2]: {
 						address: address2Checksum,
-						chainId: 1,
+						chainId: '1',
 						ensName: name2
 					}
 				},
 				2: {
 					[name1]: {
 						address: address1Checksum,
-						chainId: 2,
+						chainId: '2',
 						ensName: name1
 					}
 				}
@@ -102,29 +102,29 @@ describe('EnsController', () => {
 	it('should throw on attempt to set invalid ENS entry', () => {
 		const controller = new EnsController();
 		expect(() => {
-			controller.set(1, '1337', 'foo');
+			controller.set('1', '1337', 'foo');
 		}).toThrowError();
 		expect(controller.state).toEqual({ ensEntries: {} });
 	});
 
 	it('should remove an ENS entry and return true', () => {
 		const controller = new EnsController();
-		expect(controller.set(1, name1, address1)).toBeTruthy();
-		expect(controller.delete(1, name1)).toBeTruthy();
+		expect(controller.set('1', name1, address1)).toBeTruthy();
+		expect(controller.delete('1', name1)).toBeTruthy();
 		expect(controller.state).toEqual({ ensEntries: {} });
 	});
 
 	it('should return false if an ENS entry was NOT deleted', () => {
 		const controller = new EnsController();
-		controller.set(1, name1, address1);
-		expect(controller.delete(1, 'bar')).toBeFalsy();
-		expect(controller.delete(2, 'bar')).toBeFalsy();
+		controller.set('1', name1, address1);
+		expect(controller.delete('1', 'bar')).toBeFalsy();
+		expect(controller.delete('2', 'bar')).toBeFalsy();
 		expect(controller.state).toEqual({
 			ensEntries: {
 				1: {
 					[name1]: {
 						address: address1Checksum,
-						chainId: 1,
+						chainId: '1',
 						ensName: name1
 					}
 				}
@@ -134,23 +134,23 @@ describe('EnsController', () => {
 
 	it('should add multiple ENS entries and remove without side effects', () => {
 		const controller = new EnsController();
-		expect(controller.set(1, name1, address1)).toBeTruthy();
-		expect(controller.set(1, name2, address2)).toBeTruthy();
-		expect(controller.set(2, name1, address1)).toBeTruthy();
-		expect(controller.delete(1, name1)).toBeTruthy();
+		expect(controller.set('1', name1, address1)).toBeTruthy();
+		expect(controller.set('1', name2, address2)).toBeTruthy();
+		expect(controller.set('2', name1, address1)).toBeTruthy();
+		expect(controller.delete('1', name1)).toBeTruthy();
 		expect(controller.state).toEqual({
 			ensEntries: {
 				1: {
 					[name2]: {
 						address: address2Checksum,
-						chainId: 1,
+						chainId: '1',
 						ensName: name2
 					}
 				},
 				2: {
 					[name1]: {
 						address: address1Checksum,
-						chainId: 2,
+						chainId: '2',
 						ensName: name1
 					}
 				}
@@ -160,9 +160,9 @@ describe('EnsController', () => {
 
 	it('should clear all ENS entries', () => {
 		const controller = new EnsController();
-		expect(controller.set(1, name1, address1)).toBeTruthy();
-		expect(controller.set(1, name2, address2)).toBeTruthy();
-		expect(controller.set(2, name1, address1)).toBeTruthy();
+		expect(controller.set('1', name1, address1)).toBeTruthy();
+		expect(controller.set('1', name2, address2)).toBeTruthy();
+		expect(controller.set('2', name1, address1)).toBeTruthy();
 		controller.clear();
 		expect(controller.state).toEqual({ ensEntries: {} });
 	});