It might appear to be a bad April Fool's joke but it was no laughing matter for 30,000 applicants to the University of California San Diego.

Campus officials e-mailed acceptance letters to the students who should have received rejection letters.

The e-mail invited students to an orientation and started by saying "we're thrilled that you've been admitted."

The university caught the mistake within two hours and sent out another e-mail apologizing for the "level of distress" they had caused.

Cornell University and the University of North Carolina have reported similar mix-ups in the past.