Meghan has banned Prince Harry from drinking tea and coffee, a royal insider has claimed.

The reformed party animal had already reportedly given up alcohol out of sympathy for pregnant Meghan, but now he's drinking mineral water instead of caffeine, the Sunday Express reports.

The Duke of Sussex's new health kick meant he looked fitter and bright-eyed at Sandringham for Christmas - and it hasn't gone unnoticed by the royal family.

A source told the Express: 'Considering he's been a pretty brutal drinker since he was a young teenager, it's quite an achievement.'

The Duchess of Sussex, 37, has also introduced Harry to yoga and has encouraged him to exercise more, showing him an alternative way to live claims the source.

Meghan Markle has reportedly banned Prince Harry from drinking caffeine and booze. Pictured: The Duke and Duchess of Sussex toasting at a summer party in Dublin in July

Instead of cocktails or tea, Harry, pictured at a Block Party in 2012 in Belmopan, Belize, is drinking mineral water

The new exercise regime and lack of booze has meant that friends think the 34 year old is 'more chilled and relaxed'.

A source said: 'All she did was show him there's another way to live and he's become a huge fan.

'He eats well, doesn't poison his body, exercises, does a bit of yoga and is a lot happier.'

MailOnline has contacted Kensington Palace for a comment.

Back in October, Harry was spotted toasting with water at a state dinner at the Grand Pacific Hotel - and was praised for supporting his pregnant wife.

The Duke of Sussex's new health kick meant he looked fitter and bright-eyed at Sandringham for Christmas (pictured) - and it hasn't gone unnoticed by the royal family

The new healthy Harry is a far cry from the party-loving Prince who was photographed naked in a Las Vegas hotel room after playing 'strip billiards' back in 2012. Pictured: Harry in Belize in 2012

Meghan has been shaking up the royal family since marrying Prince Harry at Windsor Castle in May, and even made some changes before joining the firm.

She reportedly convinced Prince Harry to give up smoking in March, and the royal has been working out at the exclusive KX private members health club in Chelsea to 'get his soldier body back'.

The new healthy Harry is a far cry from the royal who was photographed naked in a Las Vegas hotel room after playing 'strip billiards' back in 2012.

His partying antics are infamous, with the young royal partying the night away with a close group of friends.

In 2011, he was caught on camera jumping into a pool fully clothed while drinking in Hvar, Croatia.