diff --git a/src/lpython/semantics/python_ast_to_asr.cpp b/src/lpython/semantics/python_ast_to_asr.cpp
index 63c87dbe4a..910735498f 100644
--- a/src/lpython/semantics/python_ast_to_asr.cpp
+++ b/src/lpython/semantics/python_ast_to_asr.cpp
@@ -2927,6 +2927,9 @@ class CommonVisitor : public AST::BaseVisitor<Struct> {
         if( !init_expr ) {
             tmp = nullptr;
             if (x.m_value) {
+                if (AST::is_a<AST::JoinedStr_t>(*x.m_value)) {
+                    throw SemanticError("f-strings are not implemented yet", x.m_value->base.loc);
+                }
                 this->visit_expr(*x.m_value);
             } else {
                 if (ASR::is_a<ASR::StructType_t>(*type)) {
@@ -7247,6 +7250,8 @@ class BodyVisitor : public CommonVisitor<BodyVisitor> {
             AST::Call_t *c = AST::down_cast<AST::Call_t>(x.m_value);
             visit_Call(*c);
             return;
+        } else if (AST::is_a<AST::JoinedStr_t>(*x.m_value)) {
+            throw SemanticError("f-strings are not implemented yet", x.m_value->base.loc);
         }
         this->visit_expr(*x.m_value);