diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/syncKotlinAndAndroidSourceSets.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/syncKotlinAndAndroidSourceSets.kt
index c1c7ae33777..1956643eefa 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/syncKotlinAndAndroidSourceSets.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/syncKotlinAndAndroidSourceSets.kt
@@ -35,11 +35,14 @@ internal fun syncKotlinAndAndroidSourceSets(target: KotlinAndroidTarget) {
 }
 
 internal var AndroidSourceSet.kotlinSourceSet: KotlinSourceSet
-    get() = getConvention(KOTLIN_DSL_NAME) as KotlinSourceSet
+    get() = checkNotNull(kotlinSourceSetOrNull) { "Missing kotlinSourceSet for Android source set $name" }
     private set(value) {
         addConvention(KOTLIN_DSL_NAME, value)
     }
 
+internal val AndroidSourceSet.kotlinSourceSetOrNull: KotlinSourceSet?
+    get() = getConvention(KOTLIN_DSL_NAME) as? KotlinSourceSet
+
 private fun createDefaultDependsOnEdges(
     target: KotlinAndroidTarget,
     kotlinSourceSet: KotlinSourceSet,