Big news in the world of mid-level to high-level cameo spots! First up: Justin Bieber continues his grand tour of every single conceivable corner of the pop-culture universe, having just taped a voice spot for The Simpsons. The news broke via that seminal fourth-estate institution, Justin Bieber's Twitter: "just did a voice over for the SIMPSONS!!! #swaggy," Bieber tweeted today, then deleted. Afterward, Simpsons executive producer Al Jean confirmed to EW that J.B. would indeed be stopping by Springfield for the show's 24th season: "He tries to get into a talent show that Bart is playing piano in and they won’t admit him. Draw your own conclusions." Also: "It’s a cameo, but all of his fans should watch every minute of the show, before and after he’s on.” That would be very #swaggy indeed!

She’s voiced a Smurf, she’s cameoed on How I Met Your Mother, she’s hosted SNL, and now Katy Perry has played a batty Raising Hope prison guard with a mustache! Last night Perry dropped in on the Fox family drama and acquitted herself nicely in limited screen time. Apparently Shannon Woodward, who plays Sabrina on Hope, is Perry’s best friend (Rihanna’s like WTF, Katy), so presumably the pop star wanted to hop on in order to give her pal’s show a boost. (The storyline is that Sabrina has belatedly joined up with the Occupy protests, and finds her way to the slammer in the process.) HitFix wonders if it matters: “Stunt-casting rarely moves the ratings needle in this day and age, and I don't know that Perry fans are going to want to tune in to see her so de-glammed, but at least it gives FOX something to promote.”