Ariana Grande has penned a heartfelt letter to her fans after she was seen crying on stage while performing during her Sweetener world tour.

The American pop star opened up in a lengthy post on social media, which she has since deleted, explaining how grateful she was to have her voice and the opportunity to perform for thousands of people.

In the post, the 26-year-old said: "If you too are hurting, you can push through and are not alone."

She also thanked her fans for accepting her "humanness", saying she sometimes cried a lot because she was touring at a time in her life when she was "still processing a lot".

Ariana Grande performing during the One Love Manchester benefit concert last year. Credit: PA

Grande has encountered a number of hardships in recent years, particularly the death of ex-boyfriend Mac Miller and the Manchester Arena terror attack which took place after her concert fininshed, killing 22 people in May 2017.

Behaviour, Media and Celebrity Psychologist, Behaviour, Media and Celebrity Psychologist, Jo Hemmings told ITV News that Grande's performances and not letting her fans down is important to her happiness.

"Ariana has had a particularly tough time of late and will be feeling emotionally and physically drained, but like a lot of hard working and conscientious performers, she feels she has a responsibility not to let her fans down, and this is important to her ultimate well-being," she said.

She continued: "Understanding and accepting that while she may struggle to contain her emotions during the pressure of a performance, releasing her emotions during these overwhelming moments are part of the process of recovery and along with the enduring support of her family, friends and fans, she will get through this in due course."

Ariana Grande's former partner Mac Miller, who died last year. Credit: PA

Agents have said it is best to help artists who are going through a tough time by creating a peaceful vibe.

Talent Agent Luca Carluccio, who works for entertainment agency mn2s, told ITV News: "It wouldn’t be just me trying to solve the situation.

"The whole team would support the artist: manager, tour manager, etc.

"The morning after the show, we would sit down together with the artist to discuss what and why that happened."

He added: "If it is something personal related, then I would avoid additional stress and try keep the artist on a peaceful vibe to focus on her next live performance.

"Maybe a sauna or a tour of the city.

"Then ask if they're up for continuing the tour.

"There’s nothing bad with re-scheduling some dates, health (and mental health) comes first!"

Ariana Grande (left) and Miley Cyrus (right) performing during the One Love Manchester benefit concert. Credit: PA

In the since deleted post, the singer thanked her fans and said she was grateful for working with the best musicians and dancers in the world.

She said: "I feel everything very intensely and have committed to doing this tour during a time in my life when I'm still processing a lot ... so sometimes I cry a lot!"

Grande said she wrote the message "because I'm grateful and because I want you to know that if you too are hurting, you can push through and are not alone".

She added: "It is hard to balance taking care of the people around you, doing your job, and healing/ taking care of yourself at the same time... but I want you to know, you aren't alone and I think you're doing great.

"Love you."

Many fans have also expressed concern for the singer, with some even suggesting she should postpone tour dates.

The Sweetener World Tour began in Albany, New York, in March.

Grande is set to perform in the UK and Ireland later this year, with dates in London, Birmingham, Glasgow, Sheffield and Dublin planned.

She will also headline Manchester Pride in August, returning to the city more than two years after the suicide bomb attack at her concert.