diff --git a/include/nlohmann/detail/output/binary_writer.hpp b/include/nlohmann/detail/output/binary_writer.hpp
index d0c947bba..6c2ad70bc 100644
--- a/include/nlohmann/detail/output/binary_writer.hpp
+++ b/include/nlohmann/detail/output/binary_writer.hpp
@@ -1634,7 +1634,9 @@ class binary_writer
         };
 
         string_t key = "_ArrayType_";
-        auto it = bjdtype.find(static_cast<string_t>(value.at(key)));
+        // use get<string_t>() instead of static_cast<string_t> to avoid an
+        // ambiguous conversion under explicit instantiation on C++17 (see #4825)
+        auto it = bjdtype.find(value.at(key).template get<string_t>());
         if (it == bjdtype.end())
         {
             return true;
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 36c1f1510..5c661684d 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -17820,7 +17820,9 @@ class binary_writer
         };
 
         string_t key = "_ArrayType_";
-        auto it = bjdtype.find(static_cast<string_t>(value.at(key)));
+        // use get<string_t>() instead of static_cast<string_t> to avoid an
+        // ambiguous conversion under explicit instantiation on C++17 (see #4825)
+        auto it = bjdtype.find(value.at(key).template get<string_t>());
         if (it == bjdtype.end())
         {
             return true;