diff --git a/lib/index.d.ts b/lib/index.d.ts
index 9cef179..b12410d 100644
--- a/lib/index.d.ts
+++ b/lib/index.d.ts
@@ -88,7 +88,7 @@ export interface OptionalOptions {
      * * Twitter supports `force_login`, `screen_name`.
      * * Linkedin supports `fields`.
      */
-    providerParams?: StringLikeMap | ((request: Request) => StringLikeMap) | undefined;
+    providerParams?: StringLikeMap | ((request: Request) => StringLikeMap | Promise<StringLikeMap>) | undefined;
     /**
      * allows passing query parameters from a bell protected endpoint to the auth request.
      * It will merge the query params you pass along with the providerParams and any other predefined ones.
@@ -129,7 +129,7 @@ export interface OptionalOptions {
      * It may be passed either as an object to merge into the query string,
      * or a function which takes the client's request and returns an object.
     */
-    tokenParams?: StringLikeMap | ((request: Request) => StringLikeMap) | undefined;
+    tokenParams?: StringLikeMap | ((request: Request) => StringLikeMap | Promise<StringLikeMap>) | undefined;
     /**
      * an object of key-value pairs that specify additional
      * URL query parameters to send with the profile request to the provider.
@@ -307,4 +307,4 @@ export function simulate(credentialsFunc: RequestPassThrough): void;
  * [See docs](https://github.com/hapijs/bell/blob/master/API.md#simulated-authentication)
  * Disables simulation mode
  */
-export function simulate(state: false): void;
\ No newline at end of file
+export function simulate(state: false): void;
diff --git a/lib/oauth.js b/lib/oauth.js
index 408b349..c5ed55e 100755
--- a/lib/oauth.js
+++ b/lib/oauth.js
@@ -73,7 +73,7 @@ exports.v1 = function (settings) {
             h.state(cookie, state);
 
             const authQuery = {
-                ...internals.resolveProviderParams(request, settings.providerParams),
+                ...await internals.resolveProviderParams(request, settings.providerParams),
                 oauth_token: temp.oauth_token,
                 ...(settings.allowRuntimeProviderParams && request.query)
             };
@@ -178,7 +178,7 @@ exports.v2 = function (settings) {
 
             const nonce = Cryptiles.randomAlphanumString(internals.nonceLength);
             const query = {
-                ...internals.resolveProviderParams(request, settings.providerParams),
+                ...await internals.resolveProviderParams(request, settings.providerParams),
                 ...(settings.allowRuntimeProviderParams && request.query),
                 client_id: settings.clientId,
                 response_type: 'code',
@@ -249,7 +249,7 @@ exports.v2 = function (settings) {
             grant_type: 'authorization_code',
             code: request.query.code,
             redirect_uri: internals.location(request, protocol, settings.location),
-            ...internals.resolveProviderParams(request, settings.tokenParams)
+            ...await internals.resolveProviderParams(request, settings.tokenParams)
         };
 
         if (settings.provider.pkce) {
@@ -727,7 +727,7 @@ internals.getProtocol = function (request, settings) {
 };
 
 
-internals.resolveProviderParams = function (request, params) {
+internals.resolveProviderParams = async function (request, params) {
 
-    return (typeof params === 'function' ? params(request) : params) ?? {};
+    return (typeof params === 'function' ? await params(request) : params) ?? {};
 };
diff --git a/test/oauth.js b/test/oauth.js
index 0c8506f..9f321eb 100755
--- a/test/oauth.js
+++ b/test/oauth.js
@@ -1307,6 +1307,84 @@ describe('Bell', () => {
             expect(res3.result).to.include({ endpoint: 'https://test.com' });
         });
 
+        it('authenticates an endpoint token provider parameters as a sync function', async (flags) => {
+
+            const mock = await Mock.v2(flags);
+            const server = Hapi.server({ host: 'localhost', port: 8080 });
+            await server.register(Bell);
+
+            server.auth.strategy('custom', 'bell', {
+                password: 'cookie_encryption_password_secure',
+                isSecure: false,
+                clientId: 'endpoint',
+                clientSecret: 'secret',
+                provider: mock.provider,
+                tokenParams: (_request) => ({ endpoint: 'https://sync.example.com' })
+            });
+
+            server.route({
+                method: '*',
+                path: '/login',
+                options: {
+                    auth: 'custom',
+                    handler: function (request, h) {
+
+                        return request.auth.artifacts;
+                    }
+                }
+            });
+
+            const res1 = await server.inject('/login');
+            const cookie = res1.headers['set-cookie'][0].split(';')[0] + ';';
+
+            const res2 = await mock.server.inject(res1.headers.location);
+
+            const res3 = await server.inject({ url: res2.headers.location, headers: { cookie } });
+            expect(res3.statusCode).to.equal(200);
+            expect(res3.result).to.include({ endpoint: 'https://sync.example.com' });
+        });
+
+        it('authenticates an endpoint token provider parameters as an async function', async (flags) => {
+
+            const mock = await Mock.v2(flags);
+            const server = Hapi.server({ host: 'localhost', port: 8080 });
+            await server.register(Bell);
+
+            server.auth.strategy('custom', 'bell', {
+                password: 'cookie_encryption_password_secure',
+                isSecure: false,
+                clientId: 'endpoint',
+                clientSecret: 'secret',
+                provider: mock.provider,
+                tokenParams: async (_request) => {
+
+                    await new Promise((resolve) => setTimeout(resolve, 1));
+                    return { endpoint: 'https://async.example.com' };
+                }
+            });
+
+            server.route({
+                method: '*',
+                path: '/login',
+                options: {
+                    auth: 'custom',
+                    handler: function (request, h) {
+
+                        return request.auth.artifacts;
+                    }
+                }
+            });
+
+            const res1 = await server.inject('/login');
+            const cookie = res1.headers['set-cookie'][0].split(';')[0] + ';';
+
+            const res2 = await mock.server.inject(res1.headers.location);
+
+            const res3 = await server.inject({ url: res2.headers.location, headers: { cookie } });
+            expect(res3.statusCode).to.equal(200);
+            expect(res3.result).to.include({ endpoint: 'https://async.example.com' });
+        });
+
         it('authenticates an endpoint via oauth with plain PKCE', async (flags) => {
 
             const mock = await Mock.v2(flags);