diff --git a/lisp/gnus-msg.el b/lisp/gnus-msg.el
index a2a2652..b44942b 100644
--- a/lisp/gnus-msg.el
+++ b/lisp/gnus-msg.el
@@ -1890,7 +1890,11 @@ this is a reply."
 	    (setq v
 		  (cond
 		   ((stringp value)
-		    value)
+		    (if (and (stringp match)
+			     (string-match-p "\\\\[&[:digit:]]" value)
+			     (match-beginning 1))
+			(match-substitute-replacement value nil nil group)
+		      value))
 		   ((or (symbolp value)
 			(functionp value))
 		    (cond ((functionp value)
diff --git a/texi/gnus.texi b/texi/gnus.texi
index 688d56f..b1ce15e 100644
--- a/texi/gnus.texi
+++ b/texi/gnus.texi
@@ -13459,14 +13459,20 @@ the headers of the article; if the value is @code{nil}, the header
 name will be removed.  If the attribute name is @code{eval}, the form
 is evaluated, and the result is thrown away.
 
-The attribute value can be a string (used verbatim), a function with
-zero arguments (the return value will be used), a variable (its value
-will be used) or a list (it will be @code{eval}ed and the return value
-will be used).  The functions and sexps are called/@code{eval}ed in the
-message buffer that is being set up.  The headers of the current article
-are available through the @code{message-reply-headers} variable, which
-is a vector of the following headers: number subject from date id
-references chars lines xref extra.
+The attribute value can be a string, a function with zero arguments
+(the return value will be used), a variable (its value will be used)
+or a list (it will be @code{eval}ed and the return value will be
+used).  The functions and sexps are called/@code{eval}ed in the
+message buffer that is being set up.  The headers of the current
+article are available through the @code{message-reply-headers}
+variable, which is a vector of the following headers: number subject
+from date id references chars lines xref extra.
+
+In the case of a string value, if the @code{match} is a regular
+expression, a @samp{match-substitute-replacement} is proceed on the
+value to replace the positional parameters @samp{\@var{n}} by the
+corresponding parenthetical matches (see @xref{Replacing the Text that
+Matched, , Text Replacement, elisp, The Emacs Lisp Reference Manual}.)
 
 @vindex message-reply-headers