Calvin Harris is allergic to Taylor Swift's cats.

The Scottish DJ has struck up a romance with the 'Blank Space' hitmaker but her insistence on letting her beloved furry felines Olivia Benson and Meredith Grey share her bed has caused him a problem.

A source said: ''When he stayed over at Taylor's LA house last week, Calvin says he was up all night blowing his nose and complaining he couldn't breathe.

''Apparently he's allergic to the long fluffy hair on Taylor's cats and they usually sleep in the bed so it's everywhere.''

Taylor's devotion to her pussies has caused some ''tension'' as Calvin is now reluctant to visit her at home.

The source added to heat magazine: ''He left really early the next morning - I think it's caused a bit of tension because now Calvin wants to meet up in hotel rooms or at his place in LA, but not at Taylor's house.''

The 25-year-old singer has had Meredith for three-and-a-half years and Olivia for almost a year and likes to take them everywhere with her.

Olivia has even starred in a Diet Coke advertisement with her famous owner.