diff --git a/include/openssl/ssl.h b/include/openssl/ssl.h
index 9bc43ae..03a4ea5 100644
--- a/include/openssl/ssl.h
+++ b/include/openssl/ssl.h
@@ -2728,6 +2728,13 @@
 OPENSSL_EXPORT void SSL_CTX_set_keylog_callback(
     SSL_CTX *ctx, void (*cb)(const SSL *ssl, const char *line));
 
+/* SSL_CTX_set_current_time_cb configures a callback to retrieve the current
+ * time, which should be set in |*out_clock|. This can be used for testing
+ * purposes; for example, a callback can be configured that returns a time
+ * set explicitly by the test. */
+OPENSSL_EXPORT void SSL_CTX_set_current_time_cb(
+    SSL_CTX *ctx, void (*cb)(const SSL *ssl, struct timeval *out_clock));
+
 enum ssl_renegotiate_mode_t {
   ssl_renegotiate_never = 0,
   ssl_renegotiate_once,
@@ -3825,7 +3832,8 @@
   void (*keylog_callback)(const SSL *ssl, const char *line);
 
   /* current_time_cb, if not NULL, is the function to use to get the current
-   * time. It sets |*out_clock| to the current time. */
+   * time. It sets |*out_clock| to the current time. See
+   * |SSL_CTX_set_current_time_cb|. */
   void (*current_time_cb)(const SSL *ssl, struct timeval *out_clock);
 
   /* quiet_shutdown is true if the connection should not send a close_notify on