diff --git a/src/constants.ts b/src/constants.ts
index d73f533..7075ec9 100644
--- a/src/constants.ts
+++ b/src/constants.ts
@@ -1,3 +1,3 @@
 export const simpleAccountFactoryAddress = '0x9406Cc6185a346906296840746125a0E44976454';
 
-export const dummySignature = '0xa15569dd8f8324dbeabf8023fdec36d4b754f53ce5901e283c6de79af177dc94557fa3c9922cd7af2a96ca94402d35c39f266925ee6407aeb32b31d76978d4ba1c';
\ No newline at end of file
+export const dummySignature = '0xa15569dd8f8324dbeabf8073fdec36d4b754f53ce5901e283c6de79af177dc94557fa3c9922cd7af2a96ca94402d35c39f266925ee6407aeb32b31d76978d4ba1c';
\ No newline at end of file
diff --git a/src/gasless-provider.ts b/src/gasless-provider.ts
index 459919b..2706f5a 100644
--- a/src/gasless-provider.ts
+++ b/src/gasless-provider.ts
@@ -10,6 +10,7 @@ import { getSenderAddress, signUserOperationHashWithECDSA } from 'permissionless
 import * as constants from '../src/constants';
 import { BasePaymaster } from './paymasters';
 import { PartialBy } from 'viem/types/utils';
+import { SponsorUserOperationReturnType } from 'permissionless/actions/pimlico';
 
 const log = init('hardhat:plugin:gasless');
 
@@ -144,17 +145,22 @@ export class GaslessProvider extends ProviderWrapper {
       verificationGasLimit: 0n, // dummy value
     };
 
-    const gasConfig = await this.bundlerClient.estimateUserOperationGas({
-      userOperation: {
-        ...userOperation,
-        paymasterAndData: '0x',
-      },
-      entryPoint: this._entryPoint,
-    });
+    const paymasterAndData: `0x${string}` | SponsorUserOperationReturnType =
+      await this.paymasterClient.sponsorUserOperation(userOperation, this._entryPoint);
+
+    let sponsoredUserOperation: UserOperation;
+
+    if (typeof paymasterAndData === 'string') {
+      // If our paymaster only returns its paymasterAndData and not the gas parameters, we need to estimate them ourselves
+      const gasConfig = await this.bundlerClient.estimateUserOperationGas({
+        userOperation: Object.assign(userOperation, { paymasterAndData: paymasterAndData }),
+        entryPoint: this._entryPoint,
+      });
 
-    // REQUEST PIMLICO VERIFYING PAYMASTER SPONSORSHIP
-    const sponsorUserOperationResult = await this.paymasterClient.sponsorUserOperation(userOperation, this._entryPoint);
-    const sponsoredUserOperation: UserOperation = Object.assign(userOperation, sponsorUserOperationResult);
+      sponsoredUserOperation = Object.assign(userOperation, gasConfig, { paymasterAndData: paymasterAndData });
+    } else {
+      sponsoredUserOperation = Object.assign(userOperation, paymasterAndData);
+    }
 
     // SIGN THE USER OPERATION
     const signature = await signUserOperationHashWithECDSA({
@@ -194,6 +200,16 @@ export class GaslessProvider extends ProviderWrapper {
     })) as string;
     return parseInt(rawChainId);
   }
+
+  private handlePaymasterReturnType(
+    variable: `0x${string}` | SponsorUserOperationReturnType,
+  ): `0x${string}` | SponsorUserOperationReturnType {
+    if (typeof variable === 'string') {
+      return variable;
+    } else {
+      return variable as SponsorUserOperationReturnType;
+    }
+  }
 }
 
 function getRandomBigInt(min: bigint, max: bigint): bigint {
diff --git a/src/paymasters/BasePaymaster.ts b/src/paymasters/BasePaymaster.ts
index 9a16af4..6538591 100644
--- a/src/paymasters/BasePaymaster.ts
+++ b/src/paymasters/BasePaymaster.ts
@@ -1,3 +1,4 @@
+import { SponsorUserOperationReturnType } from 'permissionless/actions/pimlico';
 import { PartialUserOperation } from '../types';
 
 export class BasePaymaster {
@@ -8,7 +9,10 @@ export class BasePaymaster {
   }
 
   // eslint-disable-next-line @typescript-eslint/no-unused-vars
-  public async sponsorUserOperation(userOp: PartialUserOperation, entryPoint: `0x${string}`): Promise<`0x${string}`> {
+  public async sponsorUserOperation(
+    userOp: PartialUserOperation,
+    entryPoint: `0x${string}`,
+  ): Promise<`0x${string}` | SponsorUserOperationReturnType> {
     throw new Error('This is a base class and should not be called directly.');
   }
 }
diff --git a/src/paymasters/PimlicoPaymaster.ts b/src/paymasters/PimlicoPaymaster.ts
index d42953a..d6115c1 100644
--- a/src/paymasters/PimlicoPaymaster.ts
+++ b/src/paymasters/PimlicoPaymaster.ts
@@ -17,12 +17,10 @@ export class PimlicoPaymaster extends BasePaymaster {
   public async sponsorUserOperation(
     userOperation: PartialUserOperation,
     entryPoint: `0x${string}`,
-  ): Promise<`0x${string}`> {
-    return (
-      await this.paymasterClient.sponsorUserOperation({
-        userOperation,
-        entryPoint,
-      })
-    ).paymasterAndData;
+  ): Promise<`0x${string}` | SponsorUserOperationReturnType> {
+    return await this.paymasterClient.sponsorUserOperation({
+      userOperation,
+      entryPoint,
+    });
   }
 }
diff --git a/src/paymasters/StackUpPaymaster.ts b/src/paymasters/StackUpPaymaster.ts
index 77dd8dc..966bc11 100644
--- a/src/paymasters/StackUpPaymaster.ts
+++ b/src/paymasters/StackUpPaymaster.ts
@@ -18,7 +18,7 @@ export class StackUpPaymaster extends BasePaymaster {
   public async sponsorUserOperation(
     userOperation: PartialUserOperation,
     entryPoint: `0x${string}`,
-  ): Promise<SponsorUserOperationReturnType> {
+  ): Promise<`0x${string}` | SponsorUserOperationReturnType> {
     return await this.paymasterClient.sponsorUserOperation({
       userOperation,
       entryPoint,