diff --git a/docs/libcurl/opts/CURLOPT_URL.3 b/docs/libcurl/opts/CURLOPT_URL.3
index 17e5c8b899..e33d866bf4 100644
--- a/docs/libcurl/opts/CURLOPT_URL.3
+++ b/docs/libcurl/opts/CURLOPT_URL.3
@@ -72,7 +72,7 @@ expected to be a sequence of characters using an ASCII compatible encoding.
 
 If libcurl is built with IDN support, the server name part of the URL can use
 an "international name" by using the current encoding (according to locale) or
-UTF-8 (when winidn is used).
+UTF-8 (when winidn is used; or a Windows Unicode build using libidn2).
 
 If libcurl is built without IDN support, the server name is used exactly as
 specified when passed to the name resolver functions.
diff --git a/lib/url.c b/lib/url.c
index e923357724..9a96e6a93b 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -62,6 +62,14 @@
 #ifdef USE_LIBIDN2
 #include <idn2.h>
 
+#if defined(WIN32) && defined(UNICODE)
+#define IDN2_LOOKUP(name, host, flags) \
+  idn2_lookup_u8((const uint8_t *)name, (uint8_t **)host, flags)
+#else
+#define IDN2_LOOKUP(name, host, flags) \
+  idn2_lookup_ul((const char *)name, (char **)host, flags)
+#endif
+
 #elif defined(USE_WIN32_IDN)
 /* prototype for curl_win32_idn_to_ascii() */
 bool curl_win32_idn_to_ascii(const char *in, char **out);
@@ -1585,12 +1593,12 @@ CURLcode Curl_idnconvert_hostname(struct Curl_easy *data,
 #else
       int flags = IDN2_NFC_INPUT;
 #endif
-      int rc = idn2_lookup_ul((const char *)host->name, &ace_hostname, flags);
+      int rc = IDN2_LOOKUP(host->name, &ace_hostname, flags);
       if(rc != IDN2_OK)
         /* fallback to TR46 Transitional mode for better IDNA2003
            compatibility */
-        rc = idn2_lookup_ul((const char *)host->name, &ace_hostname,
-                            IDN2_TRANSITIONAL);
+        rc = IDN2_LOOKUP(host->name, &ace_hostname,
+                         IDN2_TRANSITIONAL);
       if(rc == IDN2_OK) {
         host->encalloc = (char *)ace_hostname;
         /* change the name pointer to point to the encoded hostname */