A smiling Selena Gomez looked the picture of health as she stepped out in New York on Thursday after revealing she underwent a secret kidney transplant.

The 25-year-old was spotted on the set of her next project, an untitled Woody Allen film, alongside co-star Timothee Chalamet.

But just hours before she revealed she spent the summer recovering from a kidney transplant that she had as part of her battle with Lupus, she was also hospitalised in May after suffering kidney failure whilst waiting on the transplant list.

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Beaming: Selena Gomez looked in perfect health as she stepped out on to the set of her new film, an untitled Woody Allen project, on Thursday alongside co-star Timothee Chalamet

Back on her feet: Just hours before these pictures were taken, the 25-year-old revealed she spent the summer recovering from a kidney transplant to help her battle with Lupus

The former Disney star exposed the secret in a touching Instagram post, in which she also disclosed that the donor had been her friend Francia Raisa - who later revealed she was 'grateful' to have been given the chance to help her friend.

Selena was also said to have been hospitalised in May after suffering kidney failure whilst in Chicago to see her boyfriend The Weeknd perform - who reportedly stayed by her side throughout the ordeal.

'She gave me the ultimate gift and sacrifice,' Selena wrote. 'I am incredibly blessed. I love you so much.'

Alongside the message she shared a picture of herself and Ms Raisa laying side-by-side in hospital while clutching hands.

Candid: Selena Gomez earlier revealed she underwent the surgery after receiving a donor kidney from her best friend Francia Raisa (left)

Supportive: Selena was also said to have been hospitalised in May after suffering kidney failure whilst in Chicago to see her boyfriend The Weeknd perform - who reportedly stayed by her side throughout the ordeal

Recovering: Selena was seen holding her abdomen as he got back to work after the shock revelation about her kidney failure

Holding on: The star gripped her midriff as she chatted to crew on the night

All-smiles: The brunette bombshell looked in good spirits as she threw herself into work

She also posted two other photos, including one of her surgical scar.

In an emotional statement, the former Disney star wrote: 'I’m very aware some of my fans had noticed I was laying low for part of the summer and questioning why I wasn’t promoting my new music, which I was extremely proud of.

'So I found out I needed to get a kidney transplant due to my Lupus and was recovering.

'It was what I needed to do for my overall health. I honestly look forward to sharing with you, soon my journey through these past several months as I have always wanted to do with you.

Recharging: Gomez is currently in New York in order to make the film, where she is also thought to be living with new flame The Weeknd

'Until then I want to publicly thank my family and incredible team of doctors for everything they have done for me prior to and post-surgery.

'And finally, there aren’t words to describe how I can possibly thank my beautiful friend Francia Raisa.

'She gave me the ultimate gift and sacrifice by donating her kidney to me. I am incredibly blessed. I love you so much sis. Lupus continues to be very misunderstood but progress is being made.'

Francia Raisa is a 29-year-old model and actress from Los Angeles, who is the daughter of radio personality Renan Coello.

Detailing her story: The singer, 25, shared three photographs alongside her emotional statement, including one of her from her hospital bed and another of her surgical scar

'She gave me the ultimate gift': Selena paid tribute to her friend Francia Raisa and said she felt 'incredibly blessed', as her pal had been the one to donate her kidney

Honest: The former Disney starlet shared her gratitude via the photo-sharing site following the surgery that has left her with a scar across the right hand side of her stomach

She has been friends with Selena since 2008, and has paid tribute to their bond in past Instagram posts.

The model also announced she was 'grateful' at having the chance to help her friend as she shared a sweet post about the operation.

She wrote: 'I am beyond grateful that God would trust me with something that not only saved a life, but changed mine in the process.

'This was part of our story, and we will share it soon, but what is important now is that this is not the only story.

'For more information regarding Lupus, please go to the Lupus Research Alliance website: www.lupusresearch.org -- Love you sis, so glad we’re on this journey together. xx'

The former Disney star was pictured in New York City yesterday before she shared news about her condition in an Instagram post

In another post from 2016, uploaded on as Selena turned 24, she wrote: 'I am obsessed with every memory we've built in the last 8 years and the ones we have yet to create.

'I am so grateful that God put you in my life when he did... I learn so much from you and I'm so so so proud of you.'

Francia made her acting debut in 2005 in an episode of action show Over There - and made her film debut in the 2006 film Bring It On: All or Nothing.

She has also appeared on the US show The Secret Life of the American Teenager - and in 2017 had a role in the critically acclaimed Netflix show, Dear White People.

Ms Gomez (pictured in New York yesterday) said she 'looked forward to sharing my journey' with fans after laying low over the summer while she recovered from the operation

In her own Instagram post, Selena also added a link to the Lupus Research Alliance website, encouraging her followers would look into the condition.

The star has been vocal about her battle with the autoimmune disease, putting her money where her mouth is in May 2016 as she announced plans to donate proceeds from ticket sales of her Revival tour to Alliance for Lupus Research.

However, just months later, she was forced to pull out of the international tour due to health concerns.

Selena previously had to cancel her Stars Dance tour in 2013 in order to undergo chemotherapy treatment for the chronic inflammatory disease.

It wasn't until October 2015 that she spoke out for the first time about her struggles with the disease, sharing details of her chemotherapy with Billboard in an interview.

When Selena announced she was cancelling the Asian and Australian leg of her tour, sources claimed she may have Lupus, while others suggested she had issues with addiction.

LUPUS: A SERIOUS AND MISUNDERSTOOD DISEASE Lupus is a chronic inflammatory disease that occurs when the body's immune system attacks its own tissues and organs. Inflammation caused by lupus can affect many different body systems — including the joints, skin, kidneys, blood cells, brain, heart and lungs. Lupus can be difficult to diagnose because its signs and symptoms often mimic those of other ailments, and no two cases of lupus are exactly alike. In the US, 240,000 people have been diagnosed with Lupus, while it is estimated to affect around 15,000 people in the UK. The signs and symptoms of Lupus that a person experiences will depend on which body systems are affected by the disease. The most common symptoms include a butterfly-shaped rash on the face, fatigue and fever, joint pain, stiffness and swelling. Other common signs are skin lesions that get worse in the sun, shortness of breath, chest pain, dry eyes, headaches, confusion and memory loss. Some people are born with a tendency toward developing Lupus, which may be triggered by infections, certain drugs or even sunlight. While there is no cure, treatments can help control symptoms. Source: Mayo Clinic, National Institutes Of Health and NHS Choices Advertisement

Francia, 29, a model and actress from Los Angeles (left and right), has been friends with Selena since 2008 according to her social media posts

Francia revealed details about her relationship with Selena alongside this image of the pair, which she posted on the singer's 24th birthday, saying 'love you so so so much'

'I wanted so badly to say, "You guys have no idea. I’m in chemotherapy. You’re a**holes",' she told Billboard. 'I locked myself away until I was confident and comfortable again.'

Selena revealed that being the subject of relentless gossip while she was going through treatment proved to be hurtful - and subsequently made her angry.

'I'm so f***ing nice to everybody and everyone is so vile to me,' she told Billboard. 'I’ve been working since I was seven. I’ve been a UNICEF ambassador since I was 17. It’s so disappointing that I’ve become a tabloid story.'

The Blast was the first to break the news about Selena's surgery.

Her admission comes after reports recently revealed Selena has moved in with her boyfriend The Weeknd.

The Starboy hitmaker and the singer, who started dating in January, have decided to take their relationship to the next step as it is believed they are living in a lavish apartment in New York City’s Greenwich Village together.

'They are living in a low-rise luxury building in the heart of the Village. Selena is definitely immersing herself into the nitty gritty of New York,' a source told Entertainment Tonight.

It is believed the duo’s home boasts almost 12ft-high ceilings, as well as Juliette glass balconies and English kitchens.

The insider explained: 'Best of all, the master bath is outfitted with his and her vanities, a steam shower and Kohler cast-iron bathtub.'

THE FACTS ABOUT KIDNEY TRANSPLANTS Selena's best friend was probably able to give the singer the 'ultimate gift' because their blood groups matched. This is one of the three requirements that surgeons have when it comes to going ahead with the risky major surgical procedure. If blood types are not compatible, the donor still may be able to donate directly to you using treatments that lower your blood antibody levels - another test undertaken to see if the organ will be a match. Tissue typing tests (HLA) are also taken to see how well the potential donor organ would work in the new body or if it would be rejected by the immune system. Parents and children have a 50 per cent chance of matching, unrelated donors are much less likely. But it is possible to have a perfect match if the recipient has a common HLA type. Crossmatching is done multiple times throughout the transplant process. It measures antibodies in the recipient's blood and the donor cells. If it fails, it shows that the transplant cannot take place. The most common type of kidney transplants come from the deceased. But donations from relatives and friends are becoming more common. Figures suggest that in between 3 and 4 per cent of cases the donor kidneys fail because the new recipient's body has rejected the organ. Around 3,000 kidney transplants are undertaken each year in the UK, according to official NHS figures. In 2014, more than 17,000 took place in the US. The operation is carried out when the kidney loses its ability to filter waste products from the blood. This can be life-threatening. Those desperate for a new organ, but don't have a suitable living donor, are forced to wait for a suitable deceased kidney. Such waiting times can extend to five years, in which case patients are put on dialysis and advised to eat healthily, cut down on alcohol and exercise more to keep the organ functioning. Like any major surgical procedure, it comes with various risks. In the short term, it can lead to deadly blood clots and infections. Over a longer period, it can lead to weight gain, high blood pressure and even increase the risk of cancer, according to the Mayo Clinic. Advertisement

Cozy couple: The Weeknd and his girlfriend Selena Gomez have reportedly moved in together. Seen on Friday in NYC

Her big role: The former Disney star is in NYC to shoot a new Woody Allen movie with Timothee Chalamet; seen here on Monday

It is speculated that the Kill Em With Kindness musician’s accommodation costs approximately $16,000 a month to rent.

The couple normally live separately in Los Angeles, and it is not known if they have a joint pad on the West Coast.

The pair’s relocation is believed to be only a temporary stay for them both, but in the meantime they are both 'very happy' with their new home and to be settling down with one another.

The source said: 'They’ve both been very gracious to the neighbours and seem very happy with their living arrangement.'

And it is believed The Weeknd – whose real name is Abel Tesfaye – has reportedly thought about 'starting a family' with his partner.

He has even told his girlfriend about his dream for their future together.

Side by side: The couple getting coffee in Manhattan on September 3

She loves to dine with him: In a restaurant together in August

In 2015 Justin Bieber said he had lived with Gomez when they were teenagers

A separate insider previously said: 'He has thought about starting a family with Selena at some point down the line.

'Maybe in a few years. And he has told her that he would want to have a girl because nothing would be better for him then to have a cute little Selena look-alike bouncing around.

'He's mentioned to her many times that two of her would always be better than one.'

In 2015 Justin Bieber said he had lived with Gomez when they were teenagers and it was the best time of his life.

The pop star and the Texas beauty were together from 2011 until 2015.

Gomez has been seen in Manhattan for the last few weeks. On Monday she was spotted in a beige trench coat as she filmed a Woody Allen movie.