It was meant to be a warmly humorous, festive — and star-studded — TV comedy moment.
But Tom Hanks' appearance on a Saturday Night Live sketch at the weekend — flanked by younger A-listers including Scarlett Johansson and Emma Stone — sparked concern for the veteran actor's health.
During the show's recurring Five Timers Club segment, which also featured Alex Baldwin, fans noted that Hanks' hands visible trembled at times.
Although the 68-year-old Oscar-winner often kept his hands clasped together or in his pockets, they shook when he handled props, including cocktail glasses and presents.
One fan commented on X: 'Was I the only one who noticed the shakes on Tom Hanks last night on SNL?'
Other viewers suggested it wasn't the first time this 'symptom' had occurred in recent months, with another claiming: 'He was on the Graham Norton show a while back and I noticed it there too...'
MailOnline approached Hanks' representatives for comment and he recently stated he's in 'better shape' in his late 60s than he was in his 30s.
Meanwhile, experts have suggested a range of potential causes for shaking hands — and while it's usually nothing to worry about, it can be a sign of a serious condition.
Tom Hanks ' appearance on a Saturday Night Live sketch at the weekend sparked concern for the veteran actor's health
During the show's recurring Five Timers Club segment, fans noted that 68-year-old Oscar-winner Hanks' hands visible trembled at times
Although the Forest Gump star often kept his hands clasped together or in his pockets, they shook when he handled props, including cocktail glasses and presents
The medical term for uncontrollable shaking hanks is tremours, and these can manifest in different ways.
It is considered normal for the hands to shake a small amount — this is known as physiologic tremor and may well be most noticeable when the hands are outstretched.
Caffeine use, stress, fatigue, or sleep deprivation can intensify this sort of tremour.
A more severe shake that interferes with everyday life, however, may be a sign of a common condition known as essential tremour, or ET.
This can affect almost any part of the body, but most often in the hands, especially when carrying out simple tasks, such as drinking from a cup or tying shoelaces.
It is a neurological condition — one that affects the nerves — but medically, it is considered benign, but it usually worsens over time.
An estimated one million people in the UK have ET, and it's more common with age, with almost one in 20 over 65s affected, rising to one in five of over 95s.
'People often notice that an essential tremor is made worse with stress, a lack of sleep and coffee but, interestingly, can often improve after a small amount of alcohol,' said MailOnline resident GP Dr Ellie Cannon.
MailOnline approached Hanks' representatives for comment and he recently stated he's in 'better shape' in his late 60s than he was in his 30s
A more severe shake that interferes with everyday life, however, may be a sign of a common condition known as essential tremour, or ET
She added: 'Even if a tremour has been going on for a long time, if there has been a worsening I would say this warrants medical assessment.'
ET that causes problems may be treated with medications such as the beta blocker propranolol or the anti-seizure drug primidone, which are prescription only.
Stressful situations — such as performing in public — cause ET to worsen temporarily, and in these cases doctors may recommend taking medication ahead of the event.
Another, rarer cause of hand tremours is Parkinson's disease, an incurable condition in which parts of the brain become progressively damaged over many years.
While it can be a symptom, it is often not an early warning sign.
Alongside shaking — which can affect the whole body — the main symptoms of Parkinson's are slow movement, and stiff and inflexible muscles.
As the disease progresses, balance issues and problems with concentration and memory are often seen.
Another, rarer cause of hand tremours is Parkinson's disease, an incurable condition in which parts of the brain become progressively damaged over many years
Hand tremours in Parkinson's typically occur at rest — and are sometimes described as looking 'like you are rolling a pill between your thumb and index finger'.
This tremour disappears during activity — whereas in ET, the tremour only occurs during activity.
Diagnosing the cause of a tremour involves physical examination and a medical history — for instance, are there other symptoms that could indicate something more serious such as balance impairment, stiffness, or slowness of movement.
In addition, some medications can cause tremors, such as the antidepressant bupropion, and the heart drug amiodarone.
Tremours can also be an issue after a stroke, depending on which part of the brain was damaged.
If hand tremors interfere with eating, it may helpful to use weighted eating utensils and to work with a physiotherapist for help with fine motor skills, such as buttoning clothes, according to experts.
Concern was raised last year after a poll revealed the majority of people only recognise two of the 40 frequent warning signs of Parkinson's disease.
Awareness of symptoms were branded 'dangerously low' by charity, Cure Parkinson's.
This is despite an early diagnosis being key for the best chance of effective treatment and a greater quality of life for those with the condition.
Shaking and problems with balance were the only two signs widely selected by the public, at 69 and 52 per cent respectively.
Almost three quarters (74 per cent) were not aware depression, anxiety or pain could indicate a potential sign.
Over four in five (83 per cent) people didn't know losing your sense of smell is a likely sign — a symptom which can appear years before others develop.
Two thirds (66 per cent) were also unaware that physically freezing, or the temporary inability to move, could be an early warning sign.