PHILADELPHIA – A Philadelphia cable network’s early morning broadcast of Good Friday Mass at the Vatican abruptly changed to something wildly different — a 30-second “Girls Gone Wild” ad.

Comcast spokesman Jeff Alexander says the 2 a.m. Friday programming glitch was due to a required test of the Emergency Alert System. He says such tests are usually done in the overnight hours.

The test automatically tunes viewers to a preselected channel that would provide information in the event of an emergency. But during tests, the channel airs regular programming, which in this case included a paid advertisement for the racy videos.

Alexander says the problem affected the network’s entire local area, but only one person called to complain.