The last 12 months have undoubtedly been the toughest the has been forced to endure.

Hit by a shocking cancer diagnosis after abdominal surgery in January last year, the news kicked off an incredibly challenging 12 months for Kate and her family, which her husband branded 'brutal'.

Adding to their heartache, was also diagnosed with cancer, leaving brave William to step up and support his beloved wife and father. But it was Kate - who despite enduring six months of preventative chemotherapy - proved yet again what a vital member of the she is.

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From the much-needed privacy of her home on the Windsor estate, Kate guided , 11, , nine, and six-year-old through the confusion of family illness, keeping life as normal as possible for her young brood. Today, she will celebrate her 43rd birthday as she always does - by putting her family first. But former royal correspondent Jennie Bond believes she still be line for a surprise or two for husband William and her other royal relatives.

She said: "Her birthday is on a school day, so life will be the usual hectic round of getting everyone up and ready, with school bags packed. But maybe William will find time to give Catherine breakfast in bed before he looks after the kids and the school run. A rose on the breakfast tray and some luxury bath products would not go amiss."

"I expect she might want to see her parents on her birthday too as they have been such a key part of her recovery. I'm sure something very special will be winging its way towards her from the King for her birthday too. If he needed some help in choosing a gift, I’m sure Camilla would have been only too happy to help. She, too, is undoubtedly full of admiration for Catherine. I expect there will be a video call to wish her a happy birthday and to see the children making a fuss of her."

Her birthday today falls on the same day as the state funeral of former US president Jimmy Carter. But in a break with tradition, it will be who will be in Washington DC to represent Charles, rather than the heir to the throne. However, as the princess's recovery continues and she returns to royal life, Jennie believes William will be called upon to step up all the more.

She added: "I imagine that one consolation for the brutal year they’ve had is that they’ve had so much more time for family life. It’s probably going to be quite a sacrifice to re-balance things and resume full time royal work.

"There's definitely more pressure on William to step up his workload - especially as the King continues his cancer treatment. And we shall clearly be seeing more of him at numerous events. But I think he will endeavour to keep trips away from home as short as possible. The days of lengthy royal tours abroad may now be over."

The last time Kate was out in public was on Day when she joined the Royal Family for their annual Christmas Day walk to church. There she was the star attraction with well-wishers all vying to talk to her, handing her countless bouquets of flowers and other gifts.

But despite her triumphant return, it is believed her resumption of royal work will be slow and steady, with her children and her health her priority. But Jennie says there is no doubt that Kate is absolutely central to the future of the monarchy.

She explained: "She and William are way ahead in the popularity stakes, according to polls, and as we saw on Christmas Day at Sandringham, Catherine is the one who draws the biggest crowds. Everyone wants to see her, to talk to her, to photograph her.

"I think there’s an interesting parallel between the way Charles once put his own future on the line by declaring that his relationship with Camilla was 'non-negotiable', and the way Catherine has made it clear that, for the immediate future at least, her undisputed priorities are her family and her health.

"She has shown that she is very much in charge of her own agenda and that’s to be admired. The monarchy has often depended on strong women. like the late Queen and Princess Anne. Catherine takes her rightful place amongst those strong women, and I think both Charles and William believe she has all it takes to be Queen when the time comes."

In September, Kate issued a deeply personal video update on her health, saying she had finished her chemotherapy but her “path to healing and full recovery is long”, she was taking each day as it came, and was hoping to return to a light programme of public duties.

Her words were narrated over stylised footage showing the Waleses and their children enjoying the outdoors, walking through woods, and the couple cuddling as they held hands. During the Remembrance weekend in November, she appeared at the Royal Albert Hall Festival of Remembrance in honour of the nation’s war dead, and at the Cenotaph, where the Duchess of Edinburgh placed a comforting hand on Kate’s back in a show of support.

In December, the princess joined the King and William on Horse Guards Parade to welcome the Emir of to the UK at a state visit, another step on the road back to her public role. She brought Christmas cheer with her annual carol concert in Westminster Abbey, where she gathered with William and their children, other royals, and celebrities such as Paloma Faith and Richard E Grant.

Kate spoke to Faith of “challenging times” and said she had not anticipated what the past year would bring. The princess planned the service with help from Lady Gabriella Windsor, after inviting the recently-widowed Ella, whose husband, , took his own life in February, to contribute.

Louis left a touching message to his Middleton grandparents on a “kindness tree”, writing: “Thank you to granny and grandpa because they have played games with me.” Catherine Elizabeth Middleton was born to Carole and Michael Middleton on January 9 1982. She grew up in Berkshire with siblings Pippa Matthews and James Middleton. Kate met and began dating William at St Andrews University while studying History of Art.

The prince’s long-awaited proposal to his former flatmate came during a romantic holiday to Kenya, when he smuggled his late mother Diana’s sapphire and diamond engagement ring in his backpack to surprise her. The couple married in Westminster Abbey in 2011, with Kate becoming the Duchess of Cambridge and also a future queen.

The bride wore an intricate ivory gown with lace applique floral detail designed by Sarah Burton of Alexander McQueen, while the groom, on the strict instructions of his grandmother, Elizabeth II, was dressed in the red tunic of the Irish Guards. The princess has gradually and patiently developed her royal role over the years, focusing on mental health and the early years of childhood.