diff --git a/docs/kickstart/user/exec.md b/docs/kickstart/user/exec.md
new file mode 100644
index 0000000..8dc7705
--- /dev/null
+++ b/docs/kickstart/user/exec.md
@@ -0,0 +1,18 @@
+# kickstart.user.exec user command
+
+Execute `command` as `user`.
+It makes kickstart functions available to be used.
+To use variables, like `~`, quote it, otherwise it will be resolved by the current user.
+
+### Example
+
+```bash
+$ kickstart.user.exec vagrant whoami
+vagrant
+
+$ kickstart.user.exec vagrant kickstart.os
+Ubuntu
+
+$ kickstart.user.exec vagrant 'cd ~; pwd'
+/home/vagrant
+```
diff --git a/kickstart/recipes/kickstart/user.sh b/kickstart/recipes/kickstart/user.sh
index 9ce7960..84a1311 100644
--- a/kickstart/recipes/kickstart/user.sh
+++ b/kickstart/recipes/kickstart/user.sh
@@ -17,3 +17,16 @@ kickstart.user.remove_group() {
     IFS=" " read -a groups < <(id -nG $1 | sed "s/$2//") && \
     usermod -G `kickstart.print_with_separator , ${groups[*]}` $1
 }
+
+kickstart.user.exec() {
+  local user=$1
+  shift
+
+  local command=$(cat <<COMMAND
+  eval "$(kickstart infect)"
+  $@
+COMMAND
+)
+  kickstart.info "Running \"$@\" as $user"
+  su $user - bash -c "$command"
+}