His Royal Slyness is a 1920 American short comedy film featuring Harold Lloyd.

It marked the final collaboration with frequent co-star Snub Pollard, who moved on to star in his own series of films following this release.

Once he gets to the palace, he has second thoughts about replacing the prince, but he changes his mind when he sees several pretty ladies-in-waiting and Princess Florelle.

Shortly afterward, the real Prince of Razzamatazz arrives and exposes the American boy as a fraud.

The American boy accidentally fires a cannon into the palace—winning himself the new job as the country's president, while the monarchy topples.