The celebrity as a party guest isn’t anything new, but more tales of high-profile birthday bashes, anniversaries and weddings are trickling out. Take private equity baron Steve Schwartzman. He snagged Rod Stewart and Patti LaBelle to perform at his 60th birthday party in Manhattan last year. Impressive certainly, but that gathering looked like a high school performance compared to the 12-hour celeb-fest thrown in celebration of 84 Lumber founder Joe Hardy’s 84th birthday in January 2007. That soiree included musical performances by Bette Midler (backed by a full orchestra) and Christina Aguilera, who belted out Happy Birthday just for the birthday boy. After dinner, guests were surprised with a stand-up routine from Robin Williams. Russian billionaire banker Andrei Melnichenko hired Jennifer Lopez to sing at his wife’s 30th birthday party. The price tag for that 40-minute set? Reportedly as high as $2 million.

Big stars mean big prices, but hiring a celebrity doesn’t have to be a big hassle. A surprising number of stars will consider private events, for the right price of course, and a handful of companies specialize in walking you through every detail, from approaching the talent to securing the brand of bottled water they require onstage.

Find the right booker to get the star you want

Each booker works essentially the same way: they have an initial conversation with you to determine which celebrities you desire, where and when the function will take place and your budget. If your wish list doesn’t match up with your resources they’ll suggest alternate candidates. For instance, Katrina Berg Sussmeier of StarLink Productions says if you want Bette Midler or Josh Groban to sing a song at your wedding, you should be prepared to shell out at least $500,000, plus expenses. If that’s too steep, they might suggest alternate performers, like Aretha Franklin or Tom Jones, who cost less. Once the celebrity and price are agreed upon, an offer goes out directly to the star or to their agent or manager. The offer will then be accepted, rejected or negotiated. If the offer needs to be renegotiated the booker will walk you through that process.

Why comedians are cheaper than musicians

The back-up band, stylists and a celebrity’s entourage can push up those initial estimated costs significantly. Every celebrity has a rider, a list of all of the extras they require, and it can often drive up costs. Riders can tack on up to half the contract fee if a celebrity is performing and requires additional musicians or complex staging for a performance, or is simply a diva. While there is typically no appreciable difference in the fee for a popular musician versus that of a popular comedian, you might end up paying less in total for a comedian because their rider won’t require a back-up band or additional equipment. Also, keep in mind that you are almost always responsible for a celebrity’s travel arrangements—and for their entourage. Even celebrities who are not performing at an event—perhaps simply giving a toast—usually travel with at least one other person. Finally, almost all celebrities charge for hair and makeup, and some also charge a stylist fee for their wardrobe.