An emotional Ariana Grande has broken down in tears as she bid an emotional farewell to fans at her final concert before stepping back from the public eye.

The 33-year-old singer wept on stage at London’s The O2 arena on Tuesday (local time) as she wrapped up her 41-date run across the US, Canada and Britain.

“It’s been the most beautiful, extraordinary experiences of my life, and I just want to express my gratitude without sobbing completely,” a choked-up Grande told the crowd.

“Thank you from the bottom of my heart, it has been so special, and I’ll cherish this experience always, and I have the best fans in the entire world, and I always have.”

Grande confirmed a month ago that she would take time out after the conclusion of her live shows, with the final leg being a 10-date run at London’s O2 Arena.

The announcement came as the singer and Wicked star faced increased public scrutiny of her appearance and health.

It reached a peak with the release of the music video for her new single Petal, from her latest album of the same name. It was rapidly viewed millions of time on YouTube and amassed thousands of comments  – many of them about Grande’s weight loss and thinness.

The detailed scrutiny of her appearance and unsolicited health advice drew criticism for its brutal and inexorable nature.

“I feel like I’m in a Black Mirror episode. People chanting ‘Yes, yes, go queen’ on one side and the others genuinely showing concern but being shrugged off or told off,” one fan wrote.

On stage, Grande has admitted to being emotional about the tour coming to an end. On Tuesday, she tried to speak “without sobbing completely”, she said.

“I’ll cherish this experience always. I have the best fans in the entire world and I always have,” she said.

A representative for Grande told People magazine in August that the 33-year-old singer “will be taking a step back from visibility” after the tour.

“She looks forward to finishing the tour and ending it on a high note, both healthily and happily, and then taking a much-deserved break from public-facing work and appearances, which has led to endless, ongoing public scrutiny,” the statement said.

In a social media post on Monday, ahead of the penultimate night, Grande warned fans that she had to swap out her trademark 15-centimetre heeled platform boots after cutting her foot. She reassured them she was on the mend, even if she was shorter on stage.

While Grande wasn’t in her highest heels, her followers still were; the audience dressed up in her style with stilettos, cat ears and ponytails – something the star noticed.

“Thank you for all of your effort and continuing to make this so special. I have loved every minute of this with you all,” Grande said.

-with AAP