And again, this isn't some backwater college trying to make a name for themselves with an outlandish stunt. This is Cambridge. They've pretty much got their bonafides well-established at this point.
The celebrities who the sheep were trained to recognize included actors Emma Watson and Jake Gyllenhaal, BBC newsreader Fiona Bruce and Barack Obama. So, in fairness it may not have been that the sheep could be trained to recognize anyone, but just that they watch a lot of TV and DVDs and have good taste..