Jack Schlossberg, grandson of John F. Kennedy, appeared visibly heartbroken as he attended the funeral of his sister, Tatiana Schlossberg, who succumbed to cancer last week at the age of 35.

Accompanied by his mother Caroline Kennedy, father Edwin Schlossberg, and surviving sister Rose, Jack was among the mourners gathered for the service held in Manhattan on Monday.

The ceremony saw a gathering of notable figures, including former President Joe Biden, talk show legend David Letterman, and ex-U.S. Secretary of State John Kerry.

President Biden, who has experienced personal loss with the death of his son Beau to cancer in 2015, was seen shedding tears outside The Church of St. Ignatius Loyola, located in New York’s Upper East Side.

Tatiana’s passing last Tuesday followed a brave battle with leukemia, which she had publicly disclosed just six weeks prior to her death.

Her legacy includes her two young children, Josephine, aged three, and Edwin Moran, aged one, along with her husband, George Moran, who were also present at the heartfelt service.

A heavily-bearded David Letterman was seen alongside his wife, Regina Lasko, at the funeral. 

Kerry and Michael Bloomberg, the former mayor of New York City, were also in attendance. 

JFK’s grandson Jack Schlossberg looked bereft as he attended the funeral of his sister Tatiana, who died of cancer last week at the age of 35

Tatiana (pictured with her husband and kids) tragically died last Tuesday after battling Leukemia and just six weeks after she revealed her diagnosis

Former President Joe Biden, who lost his son Beau to cancer in 2015, was seen crying outside the church

Her two children, Josephine (left) and Edwin (right) Moran, and her widowed husband, George Moran (right), were also seen at the service

The Kennedy scion’s death was announced via social media accounts for the JFK Library Foundation on behalf of her heartbroken relatives.

‘Our beautiful Tatiana passed away this morning. She will always be in our hearts,’ the post reads, signed by ‘George, Edwin and Josephine Moran, Ed, Caroline, Jack, Rose and Rory.’ 

The New York-born environmental journalist revealed in November that doctors told her she had acute myeloid leukemia in May 2024.

Writing in the New Yorker, Tatiana said she had no symptoms and was ‘one of the healthiest people I knew’ when the shock diagnosis came.

Doctors only found the disease through routine blood tests after she gave birth to her second child.

It is the latest tragedy to befall Caroline, who lost her father to an assassin’s bullet when she was five years old, her only sibling, JFK Jr, in a plane crash years later, and her mother to lymphoma in 1994, when the iconic former first lady was just 64.

Writing in the New Yorker about her diagnosis, Tatiana said that she ‘could not believe’ the doctors were talking about her when they said she would need chemotherapy and a bone marrow transplant.

‘I had swum a mile in the pool the day before, nine months pregnant. I wasn’t sick. I didn’t feel sick. I was actually one of the healthiest people I knew,’ she wrote.

Caroline Kennedy is seen alongside her daughter Rose at the funeral Monday 

A heavily bearded David Letterman was seen alongside his wife, Regina Lasko, at the funeral

Secretary of State John Kerry is seen at Tatiana’s service

Mourners are seen filing out of The Church of St. Ignatius Loyola, in New York’s Upper East Side

People are seen crying and consoling one another outside the service on Monday

Tatiana said her parents and her siblings, Rose and Jack, supported her through months of grueling medical treatments.

‘[My family has] held my hand unflinchingly while I have suffered, trying not to show their pain and sadness in order to protect me from it. This has been a great gift, even though I feel their pain every day,’ she wrote.

She also addressed the so-called ‘Kennedy curse’ in her essay, saying that she did not want to add ‘a new tragedy’ to her mother Caroline’s life.

‘For my whole life, I have tried to be good, to be a good student and a good sister and a good daughter, and to protect my mother and never make her upset or angry,’ Schlossberg wrote.

‘Now I have added a new tragedy to her life, to our family’s life, and there’s nothing I can do to stop it.’

On Monday, Jack, Tatianna’s younger brother, shared a heartfelt tribute to his late sister on Instagram. 

In it, he posted ten excerpts of poems and famous texts, along with a picture of himself with his sister when they were younger. He captioned the post with a single emoji of a cherry blossom flower. 

All of the slides were in the same font and composed in the same style with consistent backgrounds, indicating that Schlossberg carefully curated the chosen texts and spent time on their presentation. 

Tatiana said her parents and her siblings, Rose and Jack, supported her through months of grueling medical treatments

Jack and Tatianna are seen together in a snap he shared to Instagram on Monday in a tribute post to his late sister 

Tatiana Schlossberg, Jack Schlossberg, Rose Schlossberg, Edwin Schlossberg and Caroline Kennedy in Ireland in 2013 to commemorate the 50th anniversary of the visit by US President JFK

The first excerpt in the slideshow featured his sister’s own words, which she wrote in her book, Inconspicuous Consumption, which is about the hidden environmental impacts of everyday consumerism and was published in 2019.

Tatiana was an environmental journalist committed to making the world a better place, as can be seen in the segment of the book shared by her brother.

‘It’s up to us to create a country that takes seriously its obligations to the planet, to each other, and to the people who will be born into a world that looks different than ours has for the past 10,000 years or so,’ Tatiana wrote.

‘Essentially, what I’m describing is hard work with possibly limited success for the rest of your life. But we have to do it, and at least we will have the satisfaction of knowing we made things better.

‘Come on, it will be fun (?),’ the excerpt concluded.