diff --git a/src/categories.cpp b/src/categories.cpp
index 16647897..e7247c2a 100644
--- a/src/categories.cpp
+++ b/src/categories.cpp
@@ -2981,9 +2981,9 @@ ucd::category ucd::lookup_category(codepoint_t c)
 	return Ii; // Invalid Unicode Codepoint
 }
 
-ucd::category_group ucd::lookup_category_group(codepoint_t c)
+ucd::category_group ucd::lookup_category_group(category c)
 {
-	switch (lookup_category(c))
+	switch (c)
 	{
 	case Cc: case Cf: case Cn: case Co: case Cs:
 		return C;
@@ -3003,3 +3003,8 @@ ucd::category_group ucd::lookup_category_group(codepoint_t c)
 		return I;
 	}
 }
+
+ucd::category_group ucd::lookup_category_group(codepoint_t c)
+{
+	return lookup_category_group(lookup_category(c));
+}
diff --git a/src/include/ucd/ucd.h b/src/include/ucd/ucd.h
index fb043e17..d206018d 100644
--- a/src/include/ucd/ucd.h
+++ b/src/include/ucd/ucd.h
@@ -96,6 +96,13 @@ namespace ucd
 		Zs, /**< @brief Space Separator */
 	};
 
+	/** @brief Lookup the General Category Group for a General Category.
+	  *
+	  * @param c The General Category to lookup.
+	  * @return  The General Category Group of the General Category.
+	  */
+	category_group lookup_category_group(category c);
+
 	/** @brief Lookup the General Category Group for a Unicode codepoint.
 	  *
 	  * @param c The Unicode codepoint to lookup.
diff --git a/tools/categories.py b/tools/categories.py
index dac66853..30367f78 100755
--- a/tools/categories.py
+++ b/tools/categories.py
@@ -173,9 +173,9 @@ using namespace ucd;
 	sys.stdout.write('}\n')
 
 	sys.stdout.write("""
-ucd::category_group ucd::lookup_category_group(codepoint_t c)
+ucd::category_group ucd::lookup_category_group(category c)
 {
-	switch (lookup_category(c))
+	switch (c)
 	{
 	case Cc: case Cf: case Cn: case Co: case Cs:
 		return C;
@@ -195,4 +195,9 @@ ucd::category_group ucd::lookup_category_group(codepoint_t c)
 		return I;
 	}
 }
+
+ucd::category_group ucd::lookup_category_group(codepoint_t c)
+{
+	return lookup_category_group(lookup_category(c));
+}
 """)