Prince William and Kate Middleton’s fourth anniversary

Catherine, Duchess of Cambridge and Prince William, Duke of Cambridge kiss on the balcony at Buckingham Palace on April 29, 2011 in London, England. The kiss was cheered on by a crowd of thousands which proved to be too noisy for one tired flower girl in this picture.

While on tour in Australia and New Zealand there were plenty of cute royal moments. Here Kate and William share a laugh after playing a friendly game of rugby with some local children in New Zealand.

The royal couple looked clucky holding some trainee police pups in at the Royal New Zealand Police College on April 16, 2014.

Kate and Wills share a laugh in front of the Sydney Harbour Bridge after arriving in Sydney.

William gives his wife an adoring look.

The Duke and Duchess giggle like school kids as they meet a koala at Taronga Zoo on April 20, 2014.

A romantic William makes his wife blush as his presents her with flowers while visiting the zoo.

The royal trio were full of smiles as they visited the zoo.

William and Kate gaze at each other while visiting the red centre on their royal tour.

The royal pair seem to enjoy each other even under the watchful gaze of the public.

The royal pair teased each other while showing off their DJ skills to some local Aussie artists.

A couple that plays together stays together. William encourages Kate to try her hand at skateboarding.

The Duchess of Cambridge comforts her husband after beating him in a friendly sailing race in Auckland while on tour of New Zealand.

Young love: Kate and William in the early days of their relationship.

The loved-up couple embrace each other for their official engagement portrait.

Kate Middleton and Prince William smile at a press conference in 2010 to announce their engagement.

Prince William and the Duchess of Cambridge walk hand-in-hand from Buckingham Palace the day after their wedding in 2011 to a waiting helicopter as they leave for a secret honeymoon location.

Kate is often snapped smiling at her husband, Prince William.

The sporty-pair in a celebratory embrace after Philip Hindes, Jason Kenny and Sir Chris Hoy of Great Britain win the gold in the Men’s Team Sprint Track Cycling final during day six of the London 2012 Olympic Games.

Prince William hugs his wife after taking part in a dragon boat race during their 2011 tour of Canada.

Duke of Cambridge receives a warm kiss from the Duchess after Prince William’s team won their round robin tournament at the Santa Barbara Racquet and Polo Club Santa Barbara, California during the royals tour of North America.

Ever the chivalrous husband, William shields his wife from the rain as the pair attend an event in London in 2012.

The hands-on pair are known for their ‘have a go’ attitude while on official tours and are often spotted laughing and smiling to each other.

Prince William placed a protective arm around his wife while the pair presented their son, Prince George, to the crowd outside their hospital after he was born July 22, 2013.

The new mum and dad seem blissfully happy as they embark on their journey into parenthood. No doubt the new additions to their family will be welcomed by royal watchers everywhere.