Just because you are a mega-rich superstar with millions of adoring fans and the money to afford the finest foods and best medicine's in the world, it doesn't mean that you won't still occasionally get ill, especially if you are a touring pop star with a busy schedule and a demanding routine to keep up with.
That being said, some of these stars remain consummate professionals and will try to soldier on when struggling with illness but sometimes this doesn't go unnoticed. Here we take a look at a few very well-known names who have performed despite not feeling in tip-top shape.
The Kiwi singing sensation has taken the world by storm since she exploded on stage with her mix of darkly poignant lyrics and catchy pop riffs and as such, she was booked for the MTV Video Music Awards show (VMAs) and by all accounts, her rehearsal was apparently 'epic'.
But, alas, the singer was struck down by flu and could not sing to the best of her ability but rather than canceling her appearance altogether, she appeared on stage in a flamboyant cocktail dress and comfy sweats and sneakers combo to provide the world with an impressive interpretive dance number. The New Zealander said she had to be hooked up to an IV drip, referring to herself as a "cute lil propped-up corpse" but she still managed to wow the audience.
2. Justin Bieber
The Biebs has many detractors and many criticisms thrown at him but not turning up to a performance is not something he undertakes lightly and this includes when he is feeling a little queasy. Whilst performing in Arizona in 2012, he vomited on stage twice but still finished his set.
A year later, in London, he suffered from breathing problems and had to take a 20-minute break from his performance at the O2 arena but still returned to the stage to finish.
Although last year she had to cancel a Grammy's performance due to bronchitis, when an illness isn't affecting her voice Rihanna will try to go on stage and this is exactly what she did in Lisbon, Portugal at the Atlantico Arena.
The Badian singer had to dash off stage during her rendition of 'What's My Name' but made it back on stage for 'Rude Boy'. She later tweeted out "made it juuuust in time for RudeBoy", with her dancers covering for her while she was ill.
4. Este Haim
One of the Haim sisters and bassist for their family band Haim, Este has type 1 diabetes which means that her body can't control blood sugar levels and that she needs to inject insulin. During a 2013 performance at Glastonbury festival, she had to walk off stage as she felt her blood sugars plummeting.
Her manager rubbed chocolate inside her mouth because she'd not eaten enough and 2-minutes later she returned to finish the set with the rest of the band. She had to do it "sitting down like BB King" in her own words and she now makes sure she's always topped up.
5. Dave Grohl
In a terrible turn of events for the lead singer of the Foo Fighters, he fell off stage at a concert in Sweden in the Ulevi Stadium where it was quite evident he needed medical attention but he finished the show before being told he needed screws in his leg.
Unfortunately for the band and their fans, this meant they had to cancel their upcoming headline slot at Glastonbury festival but a month later, Grohl returned to the stage, now touring with a throne of guitars to sit on whilst his leg remained propped up. The band were invited back to Glastonbury the following year to perform their missed headline slot.
British rock band Marillion was booked to play the biggest chart show in the nation at the time when they were set to appear on Top of The Pops in 1985. However, disaster struck when lead singer Fish lost his voice the night before but rather than cancel, the band showed up with the singer in tow.
Fish took to the stage with a flip chart that had the lyrics to Lavender Blue on, ripping off the sheets as he went along and encouraging the audience to sing along.
7. Freddie Mercury
Diagnosed with aids in 1987, Freddie Mercury refused to confirm he had the disease when routinely questioned by the press about it and was still performing and writing songs despite his diagnosis. He disappeared from the public eye for a while but in 1990 he made his last public appearance with the rest of the band Queen to accept a Brit Award in 1990 and he was notably frail.
The song and video for 'Days of Our Lives' were recorded during the last few months of Freddie's life and it was only 24 hours before his eventual death that the star confirmed he had been suffering from aids.