diff --git a/samples/client/petstore/kotlin-retrofit2-rx3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-retrofit2-rx3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index a0251071b21..e3962e0c0f2 100644
--- a/samples/client/petstore/kotlin-retrofit2-rx3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-retrofit2-rx3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -19,7 +19,8 @@ import retrofit2.converter.moshi.MoshiConverterFactory
 class ApiClient(
     private var baseUrl: String = defaultBasePath,
     private val okHttpClientBuilder: OkHttpClient.Builder? = null,
-    private val serializerBuilder: Moshi.Builder = Serializer.moshiBuilder
+    private val serializerBuilder: Moshi.Builder = Serializer.moshiBuilder,
+    private val okHttpClient : OkHttpClient? = null
 ) {
     private val apiAuthorizations = mutableMapOf<String, Interceptor>()
     var logger: ((String) -> Unit)? = null
@@ -174,7 +175,9 @@ class ApiClient(
     }
 
     fun <S> createService(serviceClass: Class<S>): S {
-        return retrofitBuilder.client(clientBuilder.build()).build().create(serviceClass)
+        var usedClient: OkHttpClient? = null
+        this.okHttpClient?.let { usedClient = it } ?: run {usedClient = clientBuilder.build()}
+        return retrofitBuilder.client(usedClient).build().create(serviceClass)
     }
 
     private fun normalizeBaseUrl() {