diff --git a/headers/private/kernel/real_time_clock.h b/headers/private/kernel/real_time_clock.h
index 960ef2c157..b2aab5ae01 100644
--- a/headers/private/kernel/real_time_clock.h
+++ b/headers/private/kernel/real_time_clock.h
@@ -17,7 +17,10 @@ status_t rtc_init(kernel_args *args);
 bigtime_t rtc_boot_time(void);
 	// Returns the time at which the system was booted in microseconds since Jan 1, 1970.
 
+status_t set_tzspecs(int32 timezone_offset, bool dst_observed);
+
 status_t _user_set_real_time_clock(uint32 time);
+status_t _user_set_tzspecs(int32 timezone_offset, bool dst_observed);
 
 #ifdef __cplusplus
 }
diff --git a/headers/private/kernel/real_time_data.h b/headers/private/kernel/real_time_data.h
index e889996d93..7595c45fc8 100644
--- a/headers/private/kernel/real_time_data.h
+++ b/headers/private/kernel/real_time_data.h
@@ -15,6 +15,8 @@
 struct real_time_data {
 	uint64	boot_time;
 	uint32	system_time_conversion_factor;
+	bigtime_t	timezone_offset;
+	bool	dst_observed;
 };
 
 #endif	/* _KERNEL_REAL_TIME_DATA_H */
diff --git a/headers/private/kernel/syscalls.h b/headers/private/kernel/syscalls.h
index 4e8af4a511..99e8968e59 100644
--- a/headers/private/kernel/syscalls.h
+++ b/headers/private/kernel/syscalls.h
@@ -184,6 +184,7 @@ extern status_t		_kern_stop_watching(dev_t device, ino_t node, uint32 flags,
 
 // time functions
 extern status_t		_kern_set_real_time_clock(uint32 time);
+extern status_t		_kern_set_tzspecs(int32 timezone_offset, bool dst_observed);
 
 // area functions
 area_id _kern_create_area(const char *name, void **address, uint32 addressSpec,