Addressing the graduating class of UCLA sounds like a positive, prestigious gig for most celebs—so why are they having so much trouble lining up a speaker?

First, Hollywood heartthrob James Franco bailed at the last minute, claiming he had to be on the set of his next film for “pre-production.” Does that mean he has to stand around while they build the sets?

So a group of enterprising UCLA students set up a page on Facebook, hoping to lure new “The Tonight Show” host Conan O’Brien into subbing for Franco. Alas, Conan turned them down. He released this statement, as reported by TMZ, “I am honored to be asked but I am so busy launching ‘The Tonight Show’ there just is not enough time to give this speech the preparation it deserves. I wish everyone in the class of 2009 the best and I am honored that they thought of me.”

Spoilsport! Conan should go for it! It would be great PR for his new job, and might take the media’s focus off his disappointing ratings. Besides, he could always have his staff of writers craft a speech and read it off the teleprompter.

Does he have a big bowling date or something happening? “Pineapple Express” actor James Franco seems to think he has better things to do than address his alma mater.

The hunky heartthrob was scheduled to deliver the commencement speech to UCLA’s College of Letters and Science graduates on June 12, but Franco has cancelled the date, releasing this statement: “I deeply regret not being able to keep my commitment to giving the commencement speech at UCLA’s graduation this year. Unfortunately the date conflicts with me needing to be on location to begin pre-production on my next film. I wish everyone in the 2009 class the best of luck in all of their future endeavors.”

It’s hard to believe that Franco couldn’t get a little time off from “pre-production.” That means the movie’s not even shooting yet. Maybe he’s afraid he’d fall asleep at the podium—like he was prone to doing in class.