Princesses Maria Carolina, 20, and Maria Chiara of Bourbon

Princesses Maria Carolina and Maria Chiara of Bourbon-Two Sicilies looked elegant in casual attire as they attended a tennis tournament in Monte Carlo yesterday.

The Italian heiresses, 19 and 20, were chic in pastel blouses and denim for their outing in Monaco, with Chiara opting to complete her simple ensemble with a bright red baseball cap.

Despite the casual outfit, the 19-year-old heiress looked typically put together, carrying a designer bag and keeping her make-up clean and flawless for the day.

Her blonde locks were loose around her shoulders and very lightly curled.

Meanwhile, Chaira's older sister Carolina was equally as poised, opting to wear sunglasses on her head rather than a baseball cap.

Princesses Maria Carolina and Maria Chiara of Bourbon-Two Sicilies looked elegant in casual attire as they attended a tennis tournament in Monte Carlo yesterday

She completed her tennis day outfit with double gold hoops and pink-toned make-up.

The heiress' father Prince Carlo, Duke of Castro, 60, holds a claim to the now defunct throne of the former House of Bourbon-Two Sicilies. 

Their outing comes after Chaira was forced to squash rumours that she was dating Denmark's future king 18-year-old Prince Christian, the son of King Frederick X and Queen Mary.

Rumours that Chiara and Christian were close began when the two were pictured together at the Monaco grand prix last year.

Eventually Chiara took to Instagram and appeared to dismiss the speculation, saying 'while we all enjoy dreaming of fairytales, what truly matters is reality.' Meanwhile, the Danish royal family remained quiet on the speculation.

Chiara told Italian paper Corriere: 'We've known each other since we were little, my father Carlo is godfather to his younger sister.'

But it was her hint that she 'hopes to meet Queen Margrethe soon' which sent rumours of an engagement into overdrive.  

The Italian heiresses, 19 and 20, were chic in pastel blouses and denim for their outing in Monaco, with Chiara opting to complete her simple ensemble with a bright red baseball cap

The heiress' father Prince Carlo, Duke of Castro, 60, holds a claim to the now defunct throne of the former House of Bourbon-Two Sicilies

Her father Prince Carlo holds a claim to the now defunct throne of the former House of Bourbon-Two Sicilies, a cadet branch of the Spanish royal family. 

While, her mother, Duchess Camilla, is the daughter of Italian industry Tycoon Camilla Crociani.

Chiara and her older sister enjoy a life of luxury, spending their time between Italy, Monaco, Paris and Saint-Tropez, soaking up the sun, sporting designer labels and making the most of their family's wealth.

Their outing comes after Chaira was forced to squash rumours that she was dating Denmark's future king, 18-year-old Prince Christian, the son of King Frederick X and Queen Mary 

They are also actively involved with charity work and rub shoulders with the most elite socialites of Europe, speaking English, French and Italian fluently.

The two princesses regularly share snaps of their glamorous lifestyles on Instagram, posting pictures from destinations around the globe, from Paris to Dubai and New York.

Because Chiara is the younger sibling, she will not inherit her father's title and duties, or his claim to Head of the House of Bourbon-Two Sicilies - they will go to older sister Maria Carolina, Duchess of Calabria and of Palermo (or Carolina for short).