diff --git a/include/spdlog/details/pattern_formatter-inl.h b/include/spdlog/details/pattern_formatter-inl.h
index 5fcce29e..f4efcc23 100644
--- a/include/spdlog/details/pattern_formatter-inl.h
+++ b/include/spdlog/details/pattern_formatter-inl.h
@@ -974,11 +974,13 @@ private:
 
 } // namespace details
 
-SPDLOG_INLINE pattern_formatter::pattern_formatter(std::string pattern, pattern_time_type time_type, std::string eol)
+SPDLOG_INLINE pattern_formatter::pattern_formatter(
+    std::string pattern, pattern_time_type time_type, std::string eol, custom_flags custom_user_flags)
     : pattern_(std::move(pattern))
     , eol_(std::move(eol))
     , pattern_time_type_(time_type)
     , last_log_secs_(0)
+    , custom_handlers_(std::move(custom_user_flags))
 {
     std::memset(&cached_tm_, 0, sizeof(cached_tm_));
     compile_pattern_(pattern_);
@@ -997,7 +999,12 @@ SPDLOG_INLINE pattern_formatter::pattern_formatter(pattern_time_type time_type,
 
 SPDLOG_INLINE std::unique_ptr<formatter> pattern_formatter::clone() const
 {
-    return details::make_unique<pattern_formatter>(pattern_, pattern_time_type_, eol_);
+    custom_flags cloned_custom_formatters;
+    for (auto &it : custom_handlers_)
+    {
+        cloned_custom_formatters[it.first] = it.second->clone();
+    }
+    return details::make_unique<pattern_formatter>(pattern_, pattern_time_type_, eol_, std::move(cloned_custom_formatters));
 }
 
 SPDLOG_INLINE void pattern_formatter::format(const details::log_msg &msg, memory_buf_t &dest)
@@ -1017,6 +1024,11 @@ SPDLOG_INLINE void pattern_formatter::format(const details::log_msg &msg, memory
     details::fmt_helper::append_string_view(eol_, dest);
 }
 
+SPDLOG_INLINE void pattern_formatter::recompile()
+{
+    compile_pattern_(pattern_);
+}
+
 SPDLOG_INLINE std::tm pattern_formatter::get_time_(const details::log_msg &msg)
 {
     if (pattern_time_type_ == pattern_time_type::local)
@@ -1029,6 +1041,12 @@ SPDLOG_INLINE std::tm pattern_formatter::get_time_(const details::log_msg &msg)
 template<typename Padder>
 SPDLOG_INLINE void pattern_formatter::handle_flag_(char flag, details::padding_info padding)
 {
+    auto it = custom_handlers_.find(flag);
+    if (it != custom_handlers_.end())
+    {
+        formatters_.push_back(it->second->clone());
+        return;
+    }
     switch (flag)
     {
 
diff --git a/include/spdlog/details/pattern_formatter.h b/include/spdlog/details/pattern_formatter.h
index 820f55b5..574523c5 100644
--- a/include/spdlog/details/pattern_formatter.h
+++ b/include/spdlog/details/pattern_formatter.h
@@ -14,6 +14,7 @@
 
 #include <string>
 #include <vector>
+#include <unordered_map>
 
 namespace spdlog {
 namespace details {
@@ -46,7 +47,7 @@ struct padding_info
     bool enabled_ = false;
 };
 
-class flag_formatter
+class SPDLOG_API flag_formatter
 {
 public:
     explicit flag_formatter(padding_info padinfo)
@@ -62,11 +63,19 @@ protected:
 
 } // namespace details
 
+class SPDLOG_API custom_flag_formatter : public details::flag_formatter
+{
+public:
+    virtual std::unique_ptr<custom_flag_formatter> clone() const = 0;
+};
+
 class SPDLOG_API pattern_formatter final : public formatter
 {
 public:
-    explicit pattern_formatter(
-        std::string pattern, pattern_time_type time_type = pattern_time_type::local, std::string eol = spdlog::details::os::default_eol);
+    using custom_flags = std::unordered_map<char, std::unique_ptr<custom_flag_formatter>>;
+
+    explicit pattern_formatter(std::string pattern, pattern_time_type time_type = pattern_time_type::local,
+        std::string eol = spdlog::details::os::default_eol, custom_flags custom_user_flags = {});
 
     // use default pattern is not given
     explicit pattern_formatter(pattern_time_type time_type = pattern_time_type::local, std::string eol = spdlog::details::os::default_eol);
@@ -77,6 +86,14 @@ public:
     std::unique_ptr<formatter> clone() const override;
     void format(const details::log_msg &msg, memory_buf_t &dest) override;
 
+    template<typename T, typename... Args>
+    pattern_formatter &add_flag_handler(char flag, const Args &... args)
+    {
+        custom_handlers_[flag] = details::make_unique<T>(args...);
+        return *this;        
+    }
+    void recompile();
+
 private:
     std::string pattern_;
     std::string eol_;
@@ -84,6 +101,7 @@ private:
     std::tm cached_tm_;
     std::chrono::seconds last_log_secs_;
     std::vector<std::unique_ptr<details::flag_formatter>> formatters_;
+    custom_flags custom_handlers_;
 
     std::tm get_time_(const details::log_msg &msg);
     template<typename Padder>
diff --git a/tests/test_pattern_formatter.cpp b/tests/test_pattern_formatter.cpp
index d9647f9b..04247bc5 100644
--- a/tests/test_pattern_formatter.cpp
+++ b/tests/test_pattern_formatter.cpp
@@ -246,6 +246,8 @@ TEST_CASE("paddinng_truncate_funcname", "[pattern_formatter]")
     REQUIRE(lines[1] == "message [funct]");
 }
 
+
+
 TEST_CASE("clone-default-formatter", "[pattern_formatter]")
 {
     auto formatter_1 = std::make_shared<spdlog::pattern_formatter>();
@@ -305,6 +307,43 @@ TEST_CASE("clone-formatter-2", "[pattern_formatter]")
     REQUIRE(fmt::to_string(formatted_1) == fmt::to_string(formatted_2));
 }
 
+
+class custom_test_flag : public spdlog::custom_flag_formatter
+{
+public:
+    class custom_test_flag (std::string txt) : some_txt{std::move(txt)}
+    {}
+
+    void format(const spdlog::details::log_msg &, const std::tm &, spdlog::memory_buf_t &dest) override
+    {
+        dest.append(some_txt.data(), some_txt.data() + some_txt.size());
+    }
+
+    std::string some_txt;
+
+    std::unique_ptr<custom_flag_formatter> clone() const override
+    {
+        return spdlog::details::make_unique<custom_test_flag>(some_txt);
+    }
+};
+// test clone with custom flag formatters
+TEST_CASE("clone-custom_formatter", "[pattern_formatter]")
+{
+    auto formatter_1 = std::make_shared<spdlog::pattern_formatter>("[%n] [%t] %v", spdlog::pattern_time_type::utc, "");
+    formatter_1->add_flag_handler<custom_test_flag>('t', "custom_output").recompile();    
+    auto formatter_2 = formatter_1->clone();
+    std::string logger_name = "logger-name";
+    spdlog::details::log_msg msg(logger_name, spdlog::level::info, "some message");
+
+    memory_buf_t formatted_1;
+    memory_buf_t formatted_2;
+    formatter_1->format(msg, formatted_1);
+    formatter_2->format(msg, formatted_2);    
+    
+    REQUIRE(fmt::to_string(formatted_1) == "[logger-name] [custom_output] some message");
+    REQUIRE(fmt::to_string(formatted_2) == "[logger-name] [custom_output] some message");
+}
+
 //
 // Test source location formatting
 //
@@ -358,3 +397,16 @@ TEST_CASE("full filename formatter", "[pattern_formatter]")
     formatter.format(msg, formatted);
     REQUIRE(fmt::to_string(formatted) == test_path);
 }
+
+
+TEST_CASE("custom flags", "[pattern_formatter]")
+{
+    auto formatter = std::make_shared<spdlog::pattern_formatter>("[%n] [%t] [%u] %v", spdlog::pattern_time_type::utc, "");
+    formatter->add_flag_handler<custom_test_flag>('t', "custom1").add_flag_handler<custom_test_flag>('u', "custom2").recompile();
+        
+    memory_buf_t formatted;
+    
+    spdlog::details::log_msg msg(spdlog::source_loc{}, "logger-name", spdlog::level::info, "some message");
+    formatter->format(msg, formatted);   
+    REQUIRE(fmt::to_string(formatted) == "[logger-name] [custom1] [custom2] some message");    
+}