diff --git a/diff.c b/diff.c
index 8d387280a4..574fc511ff 100644
--- a/diff.c
+++ b/diff.c
@@ -5255,6 +5255,12 @@ static void prep_parse_options(struct diff_options *options)
 			    N_("do not munge pathnames and use NULs as output field terminators in --raw or --numstat"),
 			    0),
 		OPT__ABBREV(&options->abbrev),
+		OPT_STRING_F(0, "src-prefix", &options->a_prefix, N_("<prefix>"),
+			     N_("show the given source prefix instead of \"a/\""),
+			     PARSE_OPT_NONEG),
+		OPT_STRING_F(0, "dst-prefix", &options->b_prefix, N_("<prefix>"),
+			     N_("show the given source prefix instead of \"b/\""),
+			     PARSE_OPT_NONEG),
 		OPT_CALLBACK_F(0, "output-indicator-new",
 			       &options->output_indicators[OUTPUT_INDICATOR_NEW],
 			       N_("<char>"),
@@ -5449,20 +5455,12 @@ int diff_opt_parse(struct diff_options *options,
 	}
 
 	/* misc options */
-	else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
-		options->a_prefix = optarg;
-		return argcount;
-	}
 	else if ((argcount = parse_long_opt("line-prefix", av, &optarg))) {
 		options->line_prefix = optarg;
 		options->line_prefix_length = strlen(options->line_prefix);
 		graph_setup_line_prefix(options);
 		return argcount;
 	}
-	else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
-		options->b_prefix = optarg;
-		return argcount;
-	}
 	else if (!strcmp(arg, "--no-prefix"))
 		options->a_prefix = options->b_prefix = "";
 	else if (opt_arg(arg, '\0', "inter-hunk-context",
diff --git a/parse-options.h b/parse-options.h
index 7d83e2971d..c95cbe26f0 100644
--- a/parse-options.h
+++ b/parse-options.h
@@ -136,6 +136,7 @@ struct option {
 #define OPT_BOOL_F(s, l, v, h, f)   OPT_SET_INT_F(s, l, v, h, 1, f)
 #define OPT_CALLBACK_F(s, l, v, a, h, f, cb)			\
 	{ OPTION_CALLBACK, (s), (l), (v), (a), (h), (f), (cb) }
+#define OPT_STRING_F(s, l, v, a, h, f)   { OPTION_STRING,  (s), (l), (v), (a), (h), (f) }
 
 #define OPT_END()                   { OPTION_END }
 #define OPT_ARGUMENT(l, h)          { OPTION_ARGUMENT, 0, (l), NULL, NULL, \
@@ -157,7 +158,7 @@ struct option {
 #define OPT_INTEGER(s, l, v, h)     { OPTION_INTEGER, (s), (l), (v), N_("n"), (h) }
 #define OPT_MAGNITUDE(s, l, v, h)   { OPTION_MAGNITUDE, (s), (l), (v), \
 				      N_("n"), (h), PARSE_OPT_NONEG }
-#define OPT_STRING(s, l, v, a, h)   { OPTION_STRING,  (s), (l), (v), (a), (h) }
+#define OPT_STRING(s, l, v, a, h)   OPT_STRING_F(s, l, v, a, h, 0)
 #define OPT_STRING_LIST(s, l, v, a, h) \
 				    { OPTION_CALLBACK, (s), (l), (v), (a), \
 				      (h), 0, &parse_opt_string_list }