Kate sweetly greets Duchess of Edinburgh at Christmas carol concert

The Princess of Wales has shared a sweet greeting with Sophie, Duchess of Edinburgh at her Christmas carol service.

Their special bond was proven when Kate, 42, reached out to Sophie for a touching kiss at the royal's fourth annual Together at Christmas concert inside Westminster Abbey on December 6.

For the Princess, it was her most significant public engagement since completing preventive chemotherapy treatment, and following a most gruelling year amid her shock cancer announcement in March.

Once Kate spotted the Duchess, 59, she embraced her with a warm hug and a kiss on the cheek, a fitting greeting for the royal who has provided unwavering and maternal support in her time of need.

The pair looked in their element as they reunited, while the Princess continued to show her closeness with the Duchess by placing a touching hand on her shoulder.

They were a stylish duo, with Kate donning an elegant Alexander McQueen red coat with a statement black bow; and Sophie opting for a floral bohemian style dress and white wintry blazer.

It appears the mother-of-two - who was present without her husband Prince Edward - shares a bond with Kate that also reaches their fashion choices, as her sublime look seemed to emulate the Princess's style.

As the pair have grown undeniably close over the last 13 years, it is perhaps expected they would begin to mirror one another's style.

Sophie paired her stylish look with brown boots and a white bag, along with glowing make-up and blonde tresses which were kept loose with a light curl at the end.

Meanwhile Kate teamed her festive red look with a pair of black Ralph Lauren boots, while her signature brunette locks were styled in loose waves for the occasion. 

And as Sophie at times has looked to the Princess for fashion inspiration, Kate has turned to the Duchess for a helping hand in both duty and personal matters as of late.

Since marrying into the Royal Family 25 years ago, the Duchess of Edinburgh has proven herself to be one of the Firm's key players, but lately she has stepped up to the plate in a different way - most especially for Kate.

The festive period has been a busy time, yet the Duchess of Edinburgh has been hard at work attending several engagements in recent weeks.

Whether singing carols or making mince pies, Sophie hasn't shied away from stepping up, while  Kate has been making a gradual return to duties following treatment for cancer.

Back in November, the Duchess showed her supportive side when she warmly put her arm around a Yazidi survivor while attending a photography exhibition.

Then, earlier this month, Sophie wore a glamorous gown and attended the Qatar State Banquet at Buckingham Palace with other Royals.

Days later, the Duchess of Edinburgh joined in with the festivities during a visit to the Bagshot Women's Institute and made decorations.

While at the 'Together at Christmas' carol service at Westminster Abbey, Sophie was stood by the Princess of Wales, and the following week she got stuck in with Christmas fun with the Disability Initiative charity and sang carols.

And on November 27, Sophie attended 'The Women Who Beat ISIS' photography exhibition at the Foreign, Commonwealth, and Development Office.

The event was hosted by Farida Global which supports genocide survivors and victims of conflict and religious persecution.

During her visit, Sophie met Awaz Abdi and shared a tender moment with the Yazidi survivor. She put her arm supportively around the young woman while they were walking, deep in conversation.

The Duchess also took time to look at the portraits of other Yazidi women who had been held captive by ISIS and suffered terrible horrors.

Less than a week later, Sophie was busy attending the Qatari State Banquet and dazzled in an elegant black gown.

She accompanied Qatari Energy Minister Saad Sherida al-Kaabi and wore the Wessex aquamarine tiara.

Other Royals in attendance included King Charles, Queen Camilla, Princess Anne, Prince William, Sir Timothy Laurence, Duchess of Gloucester, and Sophie's husband, Prince Edward.

Kate wasn't present at the banquet, but she did greet the Sheikh Tamim bin Hamad Al Thani and the first of his three wives, Sheikha Jawaher, on Horse Guards Parade in London. She also joined them for a private lunch at Buckingham Palace later that day.

Their sisterly bond was also observed when Sophie joined Kate on the balcony at the Foreign, Commonwealth and Development Office - where they watched the Remembrance Sunday service unfold.

As they stepped into public view, the Princess hinted to her husband's aunt that she was feeling overwhelmed - reportedly telling her: 'You're never quite ready for this...'

After reassuring the Princess, the Duchess of Edinburgh placed a supportive, 'maternal' hand on the future Queen's back as they walked back inside following the two-minute silence, which was broadcast live to the nation.

The two women, who come from similar middle-class backgrounds, have formed an undeniably close bond over the 13 years.

In the early days of Kate's relationship with Prince William, insiders claimed Sophie offered to help guide the Princess of Wales as she began her royal journey.

After marrying Prince William in 2011, the Princess of Wales is said to have found a 'mentor' in Sophie.

Having lost her own mother Mary Rhys-Jones, to stomach cancer in 2005 at just 71, Sophie had taken to affectionately calling the Queen ‘Mama’.

According to royal biographer Claudia Joseph, the Queen suggested the-then Countess of Wessex, who had become a 'second daughter' to her, take the new Duchess under her wing.