Beattie's prolific scoring coupled with his excellent all round skill has done enough to get him into the squad.
Substitutions are commonplace in England friendlies so I've no doubt that Beattie will get his first England cap. How long he gets to impress remains to be seen. On his current form, there's not a better striker available for the side. Hopefully, he'll settle in quickly and make sure he gets into squads for more serious fixtures in the future.
It's also a reminder of how far Saints have come this season. Had he been fit, Wayne Bridge would also have been in the squad. It's been a while since we had a couple of England internationals in the side.