Celebrities who gave up US citizenship
Hmmm... Here's a list of twenty of them. Hope they realize two things.
First, that they have become prohibited persons under the Gun Control Act (18 USC 922(d) and (g)(7) prohibit a person "who, having been a citizen of the United States, has renounced his citizenship" from receiving or possessing a firearm).
Second, they are forbidden to hire armed bodyguards. §922(h) makes it illegal for a person to possess firearms or ammunition "while being employed for any person described in any paragraph of subsection (g) of this section...."
UPDATE: Yep, this is one of the subsections added to GCA 68 for no particular reason beyond getting even. Another involved making anyone given a dishonorable discharge a prohibited person. The argument was, well, if he couldn't bear arms for his country he shouldn't bear arms to protect himself. The real reasons were that way back when some celebrities were renouncing citizenship (at least supposedly) to protest the Vietnam War.
Another purpose was that Congress wanted to be able to say that Lee Harvey Oswald wouldn't have been able to purchase a firearm under the law they were going to pass, and it was thought (incorrectly) that Oswald had a dishonorable discharge and had renounced his citizenship. (In fact, he had a less-than-honorable but not dishonorable discharge, and while he'd tried to renounce his citizenship he didn't jump through all the hoops correctly).