diff --git a/src/network/access/qformdatabuilder.cpp b/src/network/access/qformdatabuilder.cpp
index c0d9ce64aef..d4065c7fd22 100644
--- a/src/network/access/qformdatabuilder.cpp
+++ b/src/network/access/qformdatabuilder.cpp
@@ -8,6 +8,8 @@
 #include "QtCore/qmimedatabase.h"
 #endif
 
+#include <vector>
+
 QT_BEGIN_NAMESPACE
 
 /*!
@@ -283,19 +285,30 @@ QHttpPart QFormDataPartBuilder::build()
     \sa QHttpPart, QHttpMultiPart, QFormDataPartBuilder
 */
 
+class QFormDataBuilderPrivate
+{
+public:
+    std::vector<QFormDataPartBuilder> parts;
+};
+
 /*!
     Constructs an empty QFormDataBuilder object.
 */
 
 QFormDataBuilder::QFormDataBuilder()
-    = default;
+    : d_ptr(new QFormDataBuilderPrivate())
+{
+
+}
 
 /*!
     Destroys the QFormDataBuilder object.
 */
 
 QFormDataBuilder::~QFormDataBuilder()
-    = default;
+{
+    delete d_ptr;
+}
 
 /*!
     \fn QFormDataBuilder::QFormDataBuilder(QFormDataBuilder &&other) noexcept
@@ -324,10 +337,9 @@ QFormDataBuilder::~QFormDataBuilder()
 
 QFormDataPartBuilder &QFormDataBuilder::part(QAnyStringView name)
 {
-    static_assert(std::is_nothrow_move_constructible_v<decltype(m_parts)>);
-    static_assert(std::is_nothrow_move_assignable_v<decltype(m_parts)>);
+    Q_D(QFormDataBuilder);
 
-    return m_parts.emplace_back(name, QFormDataPartBuilder::PrivateConstructor());
+    return d->parts.emplace_back(name, QFormDataPartBuilder::PrivateConstructor());
 }
 
 /*!
@@ -338,9 +350,11 @@ QFormDataPartBuilder &QFormDataBuilder::part(QAnyStringView name)
 
 std::unique_ptr<QHttpMultiPart> QFormDataBuilder::buildMultiPart()
 {
+    Q_D(QFormDataBuilder);
+
     auto multiPart = std::make_unique<QHttpMultiPart>(QHttpMultiPart::FormDataType);
 
-    for (auto &part : m_parts)
+    for (auto &part : d->parts)
         multiPart->append(part.build());
 
     return multiPart;
diff --git a/src/network/access/qformdatabuilder.h b/src/network/access/qformdatabuilder.h
index 332a5e43166..16274734be3 100644
--- a/src/network/access/qformdatabuilder.h
+++ b/src/network/access/qformdatabuilder.h
@@ -14,7 +14,6 @@
 
 #include <memory>
 #include <variant>
-#include <vector>
 
 #ifndef Q_OS_WASM
 QT_REQUIRE_CONFIG(http);
@@ -28,6 +27,8 @@ class QHttpPartPrivate;
 class QHttpMultiPart;
 class QDebug;
 
+class QFormDataBuilderPrivate;
+
 class QFormDataPartBuilder
 {
     struct PrivateConstructor { explicit PrivateConstructor() = default; };
@@ -94,33 +95,26 @@ class QFormDataBuilder
 public:
     Q_NETWORK_EXPORT explicit QFormDataBuilder();
 
-    QFormDataBuilder(QFormDataBuilder &&other) noexcept
-        : m_parts(std::move(other.m_parts)),
-          m_reserved(std::exchange(other.m_reserved, nullptr))
-    {
-
-    }
+    QFormDataBuilder(QFormDataBuilder &&other) noexcept : d_ptr(std::exchange(other.d_ptr, nullptr)) {}
 
     QT_MOVE_ASSIGNMENT_OPERATOR_IMPL_VIA_PURE_SWAP(QFormDataBuilder)
     void swap(QFormDataBuilder &other) noexcept
     {
-        m_parts.swap(other.m_parts);
-        qt_ptr_swap(m_reserved, other.m_reserved);
+        qt_ptr_swap(d_ptr, other.d_ptr);
     }
 
     Q_NETWORK_EXPORT ~QFormDataBuilder();
     Q_NETWORK_EXPORT QFormDataPartBuilder &part(QAnyStringView name);
     Q_NETWORK_EXPORT std::unique_ptr<QHttpMultiPart> buildMultiPart();
 private:
-    std::vector<QFormDataPartBuilder> m_parts;
-    void *m_reserved = nullptr;
-
-    friend void swap(QFormDataBuilder &lhs, QFormDataBuilder &rhs) noexcept
-    { lhs.swap(rhs); }
+    QFormDataBuilderPrivate *d_ptr;
 
+    Q_DECLARE_PRIVATE(QFormDataBuilder)
     Q_DISABLE_COPY(QFormDataBuilder)
 };
 
+Q_DECLARE_SHARED(QFormDataBuilder)
+
 QT_END_NAMESPACE
 
 #endif // QFORMDATABUILDER_H