diff --git a/src/v1/auto_ml_client.ts b/src/v1/auto_ml_client.ts
index 0b04d09d..ba9e4673 100644
--- a/src/v1/auto_ml_client.ts
+++ b/src/v1/auto_ml_client.ts
@@ -155,6 +155,8 @@ export class AutoMlClient {
     }
     if (!opts.fallback) {
       clientHeader.push(`grpc/${this._gaxGrpc.grpcVersion}`);
+    } else if (opts.fallback === 'rest') {
+      clientHeader.push(`rest/${this._gaxGrpc.grpcVersion}`);
     }
     if (opts.libName && opts.libVersion) {
       clientHeader.push(`${opts.libName}/${opts.libVersion}`);
diff --git a/src/v1/prediction_service_client.ts b/src/v1/prediction_service_client.ts
index 053d1191..e8a862e6 100644
--- a/src/v1/prediction_service_client.ts
+++ b/src/v1/prediction_service_client.ts
@@ -141,6 +141,8 @@ export class PredictionServiceClient {
     }
     if (!opts.fallback) {
       clientHeader.push(`grpc/${this._gaxGrpc.grpcVersion}`);
+    } else if (opts.fallback === 'rest') {
+      clientHeader.push(`rest/${this._gaxGrpc.grpcVersion}`);
     }
     if (opts.libName && opts.libVersion) {
       clientHeader.push(`${opts.libName}/${opts.libVersion}`);
diff --git a/src/v1beta1/auto_ml_client.ts b/src/v1beta1/auto_ml_client.ts
index 9993cbcc..1745fb90 100644
--- a/src/v1beta1/auto_ml_client.ts
+++ b/src/v1beta1/auto_ml_client.ts
@@ -155,6 +155,8 @@ export class AutoMlClient {
     }
     if (!opts.fallback) {
       clientHeader.push(`grpc/${this._gaxGrpc.grpcVersion}`);
+    } else if (opts.fallback === 'rest') {
+      clientHeader.push(`rest/${this._gaxGrpc.grpcVersion}`);
     }
     if (opts.libName && opts.libVersion) {
       clientHeader.push(`${opts.libName}/${opts.libVersion}`);
diff --git a/src/v1beta1/prediction_service_client.ts b/src/v1beta1/prediction_service_client.ts
index ca9d2fa4..aa831a52 100644
--- a/src/v1beta1/prediction_service_client.ts
+++ b/src/v1beta1/prediction_service_client.ts
@@ -141,6 +141,8 @@ export class PredictionServiceClient {
     }
     if (!opts.fallback) {
       clientHeader.push(`grpc/${this._gaxGrpc.grpcVersion}`);
+    } else if (opts.fallback === 'rest') {
+      clientHeader.push(`rest/${this._gaxGrpc.grpcVersion}`);
     }
     if (opts.libName && opts.libVersion) {
       clientHeader.push(`${opts.libName}/${opts.libVersion}`);