diff --git a/AK/JsonValue.cpp b/AK/JsonValue.cpp
index 8a1bc99f04..e9007bf870 100644
--- a/AK/JsonValue.cpp
+++ b/AK/JsonValue.cpp
@@ -68,7 +68,7 @@ void JsonValue::copy_from(const JsonValue& other)
         m_value.as_array = new JsonArray(*other.m_value.as_array);
         break;
     default:
-        m_value.as_string = other.m_value.as_string;
+        m_value.as_u64 = other.m_value.as_u64;
         break;
     }
 }
@@ -76,7 +76,7 @@ void JsonValue::copy_from(const JsonValue& other)
 JsonValue::JsonValue(JsonValue&& other)
 {
     m_type = exchange(other.m_type, Type::Null);
-    m_value.as_string = exchange(other.m_value.as_string, nullptr);
+    m_value.as_u64 = exchange(other.m_value.as_u64, 0);
 }
 
 JsonValue& JsonValue::operator=(JsonValue&& other)
@@ -84,7 +84,7 @@ JsonValue& JsonValue::operator=(JsonValue&& other)
     if (this != &other) {
         clear();
         m_type = exchange(other.m_type, Type::Null);
-        m_value.as_string = exchange(other.m_value.as_string, nullptr);
+        m_value.as_u64 = exchange(other.m_value.as_u64, 0);
     }
     return *this;
 }
diff --git a/AK/Tests/TestJSON.cpp b/AK/Tests/TestJSON.cpp
index 31dc2c508f..ba196e4cdb 100644
--- a/AK/Tests/TestJSON.cpp
+++ b/AK/Tests/TestJSON.cpp
@@ -128,4 +128,12 @@ TEST_CASE(json_utf8_multibyte)
     EXPECT_EQ(json.as_string() ==  "\xc5\xa1", true);
 }
 
+TEST_CASE(json_64_bit_value)
+{
+    auto big_value = 0x12345678aabbccddull;
+    JsonValue big_json_value(big_value);
+    JsonValue big_json_value_copy = big_json_value;
+    EXPECT_EQ(big_json_value.as_u64(), big_json_value_copy.as_u64());
+}
+
 TEST_MAIN(JSON)