Notorious heiress Alexa Green has certainly been enjoying her most recent girls-holiday in Marbella. Just as we thought, she's been knocking back the cocktails and showing off her fabulous bikini body on the beach...

But rumour has it she's also been spotted sneaking out of Enrique Castillo's penthouse in the early hours of this morning - in nothing but her underwear! Our question is, doesn't this fiercely private billionaire know what he's letting himself in for?

Lie back on your sun lounger and get comfortable, because this summer fling is going to be a sizzler!