diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/IntrinsicifyCallsLowering.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/IntrinsicifyCallsLowering.kt
index 43063159742..292243762d4 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/IntrinsicifyCallsLowering.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/IntrinsicifyCallsLowering.kt
@@ -52,6 +52,10 @@ class IntrinsicifyCallsLowering(private val context: JsIrBackendContext) : FileL
                 op(type, OperatorNameConventions.REM, context.intrinsics.jsMod)
             }
 
+            context.irBuiltIns.string.let {
+                op(it, OperatorNameConventions.PLUS, context.intrinsics.jsPlus)
+            }
+
             context.irBuiltIns.int.let {
                 op(it, "shl", context.intrinsics.jsBitShiftL)
                 op(it, "shr", context.intrinsics.jsBitShiftR)