PRINCESS Kate is understood to be looking forward to riding in a carriage with Louis, Charlotte and George before joining them on the balcony for the King's birthday.
The Princess of Wales shared an important update this evening about her cancer treatment.
In a personally written statement released today, she admitted to making "good progress" but explains there are "good days and bad days".
And it is understood the Princess of Wales is looking forward to being in the carriage with her children for the event.
It comes as....
Kate will ride in a carriage with Prince George, 10, Princess Charlotte, 9, and six-year-old Prince Louis, able to wave to crowds set to line The Mall.
She will watch Trooping the Colour before appearing with the King, William and other royals, on Buckingham Palace balcony.
The royal mum-of-three reportedly chose the King's Birthday Parade to reappear as she would be surrounded by supportive family.
Kate wrote her treatment will be "ongoing and will be for a few more months" and is "not out of the woods yet".
But added: ";I am learning how to be patient, especially with uncertainty. Taking each day as it comes, listening to my body, and allowing myself to take this much needed time to heal."
It will be the first time the princess has appeared in public at a royal engagement since Christmas Day - an incredible 172 days ago.
Royal sources insist although Kate will appear at Trooping the Colour she is not yet returning to a full schedule of public engagements as her preventative cancer treatment continues.
But she is expected to attend more events this summer when she feels able to and with the support and guidance of her doctors.
She has also been working from home and expected to have official meetings in coming weeks and months.
In her full written statement Kate said: "I have been blown away by all the kind messages of support and encouragement over the last couple of months.
"It really has made the world of difference to William and me and has helped us both through some of the harder times.
"I am making good progress, but as anyone going through chemotherapy will know, there are good days and bad days.
"On those bad days you feel weak, tired and you have to give in to your body resting.
"But on the good days, when you feel stronger, you want to make the most of feeling well.
"My treatment is ongoing and will be for a few more months. On the days I feel well enough, it is a joy to engage with school life, spend personal time on the things that give me energy and positivity, as well as starting to do a little work from home.
By Matt Wilkinson, Royal Editor
We have some big news. The Princess of Wales will return in public for the King’s Trooping the Colour Birthday celebrations this weekend - as she continues her cancer treatment.
The princess will ride in a carriage with princes George and Louis and princess Charlotte from Buckingham Palace to Horse Guards Parade.
There she will watch Trooping the Colour before taking the carriage back to the palace and appear with the royals on the balcony.
In a personally written statement released today, describing her cancer treatment, she admits to making "good progress" but explains there are "good days and bad days".
She wrote her treatment will be "ongoing and will be for a few more months" and is "not out of the woods yet" and "taking each day as it comes."
And that she has been "blown away" by "kind messages of support" since her cancer announcement.
While this is a dramatic development coming six months since we last saw her with the Royal Family at Christmas is a shock - it is understood this is not a return to full schedule of public engagements.
Although, the princess is expected to attend events over the course of the summer.
But she has been holding meetings and is expected to appear at carefully selected events this summer, on the advice of her medical team.
We all remember The Princess of Wales went to hospital in January and later revealed in that emotional video address that she had cancer and asked for privacy as she undergoes treatments.
She has been subject to vile comments and rumours from the darker corners of the internet even when The Sun revealed a video showing her to be smiling and relaxed at Windsor Farm Shop with Prince William.
It is hoped that her appearance at Trooping will end horrendous speculation.
Palace insiders say the lies and speculation about her treatment and condition is unhelpful and places unnecessary pressure on the princess and her family.
"I’m looking forward to attending The King’s Birthday Parade this weekend with my family and hope to join a few public engagements over the summer, but equally knowing I am not out of the woods yet.
"I am learning how to be patient, especially with uncertainty. Taking each day as it comes, listening to my body, and allowing myself to take this much needed time to heal.
"Thank you so much for your continued understanding, and to all of you who have so bravely shared your stories with me."
A spokesman for Prince William said: "The Prince is pleased to see The Princess starting to engage with the work and projects that are important to her. He will continue to focus his time on supporting his wife and children, while continuing to undertake his public duties."
A spokesman for the King said: "His Majesty is delighted that the Princess is able to attend tomorrow's events, and is much looking forward to all elements of the day."
Kate was last seen at a royal engagement On Christmas Day.
She had abdominal surgery on January 16 and tests found cancer several weeks later.
December 25: The Princess of Wales joins her children and other royals for the Christmas Day walk to church at Sandringham
January 16: Kate admitted to London Clinic for planned abdominal surgery
January 29: Discharged from hospital to recuperate at home with her family
End of February: Starts chemotherapy without any publicity
March 11: The palace publishes a doctored Mother's Day photo, and Kate later apologises
March 17: The Sun reveal's Kate had been at Windsor Farm Shop with William and watched children play sport
March 18: The Sun exclusively reveals the video of Kate and William
March 22: Kate delivers an emotional statement announcing that she is having preventative cancer treatment
April 29: Kate and William mark 13th anniversary releasing unseen wedding photos
June 8: Kate does not attend Colonel's Review but letter she penned to Irish Guards reveals she said: "I do hope that I am able to represent you all once again very soon"
June 14: Kensington Palace announces the princess will attend the King's Birthday Parade
