Coffee obsessives have devised some pretty ingenious creations over the years – think meringue coffee, coffee butter spread and even a mushroom variety – but, is this new trend taking things a step too far?

Forever trying to think of new ways to rejuvenate our caffeine dependence, beverage radicals have decided to bring tonic water into the equation.

Meet the espresso tonic.

No longer the reserve of G&Ts, the bitter-tasting soda is appearing on menus in some of the world's trendsetting cities like Tokyo, Melbourne, Stockholm and Berlin, and the hashtag #espressotonic comes up with thousands of hits on Instagram.

It’s a combination that seems so inherently wrong considering the tart taste of both beverages but enthusiasts insist it’s the ultimate hybrid drink.

Some are even going as far as to create special versions by adding strange trimmings like rosemary, orange peel and includes cascara - the dried skins of coffee cherries.