So, hip-hop superstar Rihanna was too sick to fly on a private jet to Palm Beach Saturday for the highly-publicized Dana-Farber Cancer Institute fund-raising gala, but she killed on national television last night as half-time entertainment at the NBA All-Star game!

What’s more, Rihanna twittered to her fans about 3 a.m. today that she was partying up a storm in Los Angeles for her 23rd birthday!

Even worse: I’m told by gala insiders that Rihanna, who was scheduled to appear here since last fall but claimed to have bronchitis, didn’t even deign sending an apology to the gala’s guests who’d bought tables for $200,000!.

Nice going, rude girl!

Gala Chairman Paul Fireman, who once ran Reebok, did a yeoman’s job finding a replacement, Oscar winner and singer Jennifer Hudson, hours before the gala. Rihanna’s people notified Fireman on Saturday morning that she wouldn’t make it.

“If you heard Rihanna on the All-Star game, you can tell her voice isn’t 100 percent,” Fireman said. “Her pitch wasn’t high like it is usually. She didn’t want to come to Palm Beach and do a bad job. But from a breakdown came a breakthrough: We raised nearly $3 million!”