The couple, who tied the knot in October, are currently on different sides of the globe with Russell over in the US.
But a source told The Sun that they share an intimate phone call every night, but that it usually ends up being more jokey than serious.
'Katy always calls Russ when she gets back to her hotel room at night,' said the insider.
'The funny thing about Russ and Katy is that it will usually turn into them giggling or bickering over something silly.'
She has apparently also left a trail of secret notes hidden round the house, along with bits of his favourite underwear.