diff --git a/colour.c b/colour.c
index 9ac07415..92bbd71e 100644
--- a/colour.c
+++ b/colour.c
@@ -105,6 +105,21 @@ colour_split_rgb(int c, u_char *r, u_char *g, u_char *b)
 	*b = c & 0xff;
 }
 
+/* Force colour to RGB if not already. */
+int
+colour_force_rgb(int c)
+{
+	if (c & COLOUR_FLAG_RGB)
+		return (c);
+	if (c & COLOUR_FLAG_256)
+		return (colour_256toRGB(c));
+	if (c >= 0 && c <= 7)
+		return (colour_256toRGB(c));
+	if (c >= 90 & c <= 97)
+		return (colour_256toRGB(8 + c - 90));
+	return (-1);
+}
+
 /* Convert colour to a string. */
 const char *
 colour_tostring(int c)
diff --git a/format.c b/format.c
index f5d2c5f6..b34fc341 100644
--- a/format.c
+++ b/format.c
@@ -101,6 +101,7 @@ format_job_cmp(struct format_job *fj1, struct format_job *fj2)
 #define FORMAT_WINDOW_NAME 0x4000
 #define FORMAT_SESSION_NAME 0x8000
 #define FORMAT_CHARACTER 0x10000
+#define FORMAT_COLOUR 0x20000
 
 /* Limit on recursion. */
 #define FORMAT_LOOP_LIMIT 100
@@ -3555,7 +3556,7 @@ format_build_modifiers(struct format_expand_state *es, const char **s,
 
 	/*
 	 * Modifiers are a ; separated list of the forms:
-	 *      l,m,C,a,b,d,n,t,w,q,E,T,S,W,P,<,>
+	 *      l,m,C,a,b,c,d,n,t,w,q,E,T,S,W,P,<,>
 	 *	=a
 	 *	=/a
 	 *      =/a/
@@ -3572,7 +3573,7 @@ format_build_modifiers(struct format_expand_state *es, const char **s,
 			cp++;
 
 		/* Check single character modifiers with no arguments. */
-		if (strchr("labdnwETSWP<>", cp[0]) != NULL &&
+		if (strchr("labcdnwETSWP<>", cp[0]) != NULL &&
 		    format_is_end(cp[1])) {
 			format_add_modifier(&list, count, cp, 1, NULL, 0);
 			cp++;
@@ -4052,10 +4053,10 @@ format_replace(struct format_expand_state *es, const char *key, size_t keylen,
 	const char			 *errstr, *copy, *cp, *marker = NULL;
 	const char			 *time_format = NULL;
 	char				 *copy0, *condition, *found, *new;
-	char				 *value, *left, *right, c;
+	char				 *value, *left, *right;
 	size_t				  valuelen;
 	int				  modifiers = 0, limit = 0, width = 0;
-	int				  j;
+	int				  j, c;
 	struct format_modifier		 *list, *cmp = NULL, *search = NULL;
 	struct format_modifier		**sub = NULL, *mexp = NULL, *fm;
 	u_int				  i, count, nsub = 0;
@@ -4126,6 +4127,9 @@ format_replace(struct format_expand_state *es, const char *key, size_t keylen,
 			case 'b':
 				modifiers |= FORMAT_BASENAME;
 				break;
+			case 'c':
+				modifiers |= FORMAT_COLOUR;
+				break;
 			case 'd':
 				modifiers |= FORMAT_DIRNAME;
 				break;
@@ -4201,6 +4205,18 @@ format_replace(struct format_expand_state *es, const char *key, size_t keylen,
 		goto done;
 	}
 
+	/* Is this a colour? */
+	if (modifiers & FORMAT_COLOUR) {
+		new = format_expand1(es, copy);
+		c = colour_fromstring(new);
+		if (c == -1 || (c = colour_force_rgb(c)) == -1)
+			value = xstrdup("");
+		else
+			xasprintf(&value, "%06x", c & 0xffffff);
+		free(new);
+		goto done;
+	}
+
 	/* Is this a loop, comparison or condition? */
 	if (modifiers & FORMAT_SESSIONS) {
 		value = format_loop_sessions(es, copy);
diff --git a/tmux.1 b/tmux.1
index c270309f..35a87bd0 100644
--- a/tmux.1
+++ b/tmux.1
@@ -4831,6 +4831,10 @@ replaces a numeric argument by its ASCII equivalent, so
 .Ql #{a:98}
 results in
 .Ql b .
+.Ql c
+replaces a
+.Nm
+colour by its six-digit hexadecimal RGB value.
 .Pp
 A limit may be placed on the length of the resultant string by prefixing it
 by an
diff --git a/tmux.h b/tmux.h
index f2957de9..e3896132 100644
--- a/tmux.h
+++ b/tmux.h
@@ -2616,6 +2616,7 @@ int	 input_key_get_mouse(struct screen *, struct mouse_event *, u_int,
 int	 colour_find_rgb(u_char, u_char, u_char);
 int	 colour_join_rgb(u_char, u_char, u_char);
 void	 colour_split_rgb(int, u_char *, u_char *, u_char *);
+int	 colour_force_rgb(int);
 const char *colour_tostring(int);
 int	 colour_fromstring(const char *s);
 int	 colour_256toRGB(int);