She's famous for her glossy chestnut locks but it seems that pregnancy has been taking a toll on the Duchess of Cambridge's beauty regime, Daily Mail reported.
Touring the West Midlands with her hair in an elegant half-up hairstyle, a glimpse of grey could be seen peeping from beneath the knot.
This is not the first time the 33-year-old royal has been snapped showing off a silver streak, with the most recent sighting coming early in January during a shopping trip.
Hair dye is one such beauty essential often given a wide berth by mothers-to-be, although celebrity hairstylist Jo Hansford says it isn't always required.
'Although colouring your hair doesn't affect pregnancy and there is no need to avoid it, some people do worry about the consequences,' she explained in an interview with MailOnline.
'Nevertheless, if someone is concerned, there are different techniques that can be used to avoid touching the scalp.
'For example, if they have an all over tint, they could revert to highlights. Alternatively, they could use a colour gloss that would add more depth and tone to the hair as well as enhancing the shine and condition.'
She adds: 'We would always recommend seeking advice from a specialist before booking an appointment.'
The Duchess is no stranger to hair dye and reportedly booked an emergency appointment with colourist Rossano Ferretti after unflattering photos of her greys were published in November 2013.
According to witnesses, Kate left his salon 'looking amazing' and with her locks appearing 'big and glossy' after a £600 six-hour session with the Italian stylist.
But like many 30-something women, greys have become an increasingly regular occurrence for Kate, with friends saying the Duchess first began noticing hers in the run-up to becoming pregnant with Prince George.
To combat these, she had organic vegetable-based dye and subtle low-lights applied during regular four-hour visits to the Richard Ward Hair And Metrospa in Chelsea.
'Going grey marks nature's way of softening the hair colour giving natural highlights as the skin pigmentation changes,' says celebrity stylist Daniel Galvin Jr.
'I always recommend using a semi-permanent colour with no ammonia or peroxide, to blend the grey hair and tone it down slightly.'
However, the NHS says new mothers and pregnant women needn't avoid the salon: 'The chemicals in permanent and semi-permanent hair dyes are not highly toxic,' says its website.
'Most research, although limited, shows that it's safe to colour your hair while pregnant. Some studies have found that very high doses of the chemicals in hair dyes may cause harm.
'However, these doses are massive compared to the very low amount of chemicals a woman is exposed to when colouring her hair.'
Celebrity hair stylist Errol Douglas adds: 'I recommend vegetable dye and colour glosses to my clients when they're expecting. They're safe and take them through those months with a gentle solution to keeping roots at bay.'