http://www.look.co.uk/news/tom-hiddleston-taylor-swift-mum

Hahahha no wonder the sour faces:

'Tom's mum was very excited about Taylor coming to visit at the weekend', an insider told LOOK exclusively. 'But she had one rule - she said she was 100% putting them up in separate rooms!'

or maybe that's how they're trying to account for the sour faces in hindsight