diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt
index f8fb80f18b91fc7a7044da261e54ef25988ced99..7f0904e2933613e1da2312bec28682d3accf2a1d 100644
--- a/Documentation/git-submodule.txt
+++ b/Documentation/git-submodule.txt
@@ -8,11 +8,19 @@ git-submodule - Initialize, update or inspect submodules
 
 SYNOPSIS
 --------
+'git-submodule' [--quiet] [-b branch] add <repository> [<path>]
 'git-submodule' [--quiet] [--cached] [status|init|update] [--] [<path>...]
 
 
 COMMANDS
 --------
+add::
+	Add the given repository as a submodule at the given path
+	to the changeset to be committed next.  In particular, the
+	repository is cloned at the specified path, added to the
+	changeset and registered in .gitmodules.   If no path is
+	specified, the path is deduced from the repository specification.
+
 status::
 	Show the status of the submodules. This will print the SHA-1 of the
 	currently checked out commit for each submodule, along with the
@@ -39,6 +47,9 @@ OPTIONS
 -q, --quiet::
 	Only print error messages.
 
+-b, --branch::
+	Branch of repository to add as submodule.
+
 --cached::
 	Display the SHA-1 stored in the index, not the SHA-1 of the currently
 	checked out submodule commit. This option is only valid for the
diff --git a/git-submodule.sh b/git-submodule.sh
index 89a388535026258d65ecba3c0dd6de68e2b06cb4..67c78f2d3d9b867dd5e9c989aa6f9c4da1fbd301 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -1,13 +1,15 @@
 #!/bin/sh
 #
-# git-submodules.sh: init, update or list git submodules
+# git-submodules.sh: add, init, update or list git submodules
 #
 # Copyright (c) 2007 Lars Hjemli
 
-USAGE='[--quiet] [--cached] [status|init|update] [--] [<path>...]'
+USAGE='[--quiet] [--cached] [add <repo> [-b branch]|status|init|update] [--] [<path>...]'
 . git-sh-setup
 require_work_tree
 
+add=
+branch=
 init=
 update=
 status=
@@ -25,6 +27,18 @@ say()
 	fi
 }
 
+# NEEDSWORK: identical function exists in get_repo_base in clone.sh
+get_repo_base() {
+	(
+		cd "`/bin/pwd`" &&
+		cd "$1" || cd "$1.git" &&
+		{
+			cd .git
+			pwd
+		}
+	) 2>/dev/null
+}
+
 #
 # Map submodule path to submodule name
 #
@@ -42,6 +56,11 @@ module_name()
 #
 # Clone a submodule
 #
+# Prior to calling, modules_update checks that a possibly existing
+# path is not a git repository.
+# Likewise, module_add checks that path does not exist at all,
+# since it is the location of a new submodule.
+#
 module_clone()
 {
 	path=$1
@@ -65,6 +84,53 @@ module_clone()
 	die "Clone of '$url' into submodule path '$path' failed"
 }
 
+#
+# Add a new submodule to the working tree, .gitmodules and the index
+#
+# $@ = repo [path]
+#
+# optional branch is stored in global branch variable
+#
+module_add()
+{
+	repo=$1
+	path=$2
+
+	if test -z "$repo"; then
+		usage
+	fi
+
+	# Turn the source into an absolute path if
+	# it is local
+	if base=$(get_repo_base "$repo"); then
+		repo="$base"
+	fi
+
+	# Guess path from repo if not specified or strip trailing slashes
+	if test -z "$path"; then
+		path=$(echo "$repo" | sed -e 's|/*$||' -e 's|:*/*\.git$||' -e 's|.*[/:]||g')
+	else
+		path=$(echo "$path" | sed -e 's|/*$||')
+	fi
+
+	test -e "$path" &&
+	die "'$path' already exists"
+
+	git-ls-files --error-unmatch "$path" > /dev/null 2>&1 &&
+	die "'$path' already exists in the index"
+
+	module_clone "$path" "$repo" || exit
+	(unset GIT_DIR && cd "$path" && git checkout -q ${branch:+-b "$branch" "origin/$branch"}) ||
+	die "Unable to checkout submodule '$path'"
+	git add "$path" ||
+	die "Failed to add submodule '$path'"
+
+	GIT_CONFIG=.gitmodules git config submodule."$path".path "$path" &&
+	GIT_CONFIG=.gitmodules git config submodule."$path".url "$repo" &&
+	git add .gitmodules ||
+	die "Failed to register submodule '$path'"
+}
+
 #
 # Register submodules in .git/config
 #
@@ -173,6 +239,9 @@ modules_list()
 while case "$#" in 0) break ;; esac
 do
 	case "$1" in
+	add)
+		add=1
+		;;
 	init)
 		init=1
 		;;
@@ -185,6 +254,14 @@ do
 	-q|--quiet)
 		quiet=1
 		;;
+	-b|--branch)
+		case "$2" in
+		'')
+			usage
+			;;
+		esac
+		branch="$2"; shift
+		;;
 	--cached)
 		cached=1
 		;;
@@ -201,14 +278,27 @@ do
 	shift
 done
 
-case "$init,$update,$status,$cached" in
-1,,,)
+case "$add,$branch" in
+1,*)
+	;;
+,)
+	;;
+,*)
+	usage
+	;;
+esac
+
+case "$add,$init,$update,$status,$cached" in
+1,,,,)
+	module_add "$@"
+	;;
+,1,,,)
 	modules_init "$@"
 	;;
-,1,,)
+,,1,,)
 	modules_update "$@"
 	;;
-,,*,*)
+,,,1,*)
 	modules_list "$@"
 	;;
 *)