Meghan Markle and Prince Harry at the Natural History Museum in London

The Duchess of Sussex was the picture of elegance as she joined Prince Harry at the Natural History Museum on Tuesday night. 

Meghan, 37, who is expecting her first child in April, plumped for a custom cream roll-neck dress by Calvin Klein and a £895 coat by royal favourite Amanda Wakeley as she joined Harry, 34, to watch a play about Charles Darwin.

It is the first time the duchess has been seen in public since her father, Thomas Markle Sr, revealed the contents of a letter written by Meghan last summer in which she accused him of breaking her heart 'into a million pieces' by giving interviews to the press, fabricating stories and publicly attacking her new husband.

The letter was shared in response to allegations made by five members of Meghan's inner circle in an explosive People magazine article last week.

Today the saga continued when the Duchess' close friend George Clooney spoke out in defence of the royal, saying she is being 'pursued and vilified'.  

However any concerns appeared far from Meghan's mind as she arrived at the venue, with the Duchess flashing a broad smile for the cameras outside.

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The couple are on hand to watch behind The Wider Earth, a critically acclaimed theatrical production about the young Charles Darwin’s expedition on HMS Beagle.

The performance is being held in support of the Queen's Commonwealth Trust (QCT) and the production's official charitable partner, The Queen's Commonwealth Canopy (QCC). 

As they arrived for the performance, Meghan, 37, was given a bouquet by Sage Saunders, from London, whose father is American and mother is Canadian - which gave them much to talk about.

 The duchess was born in California and spent several years working in Toronto as an actress.

They were also introduced to the show’s producer Trish Wadley and the director of the National History Museum, Sir Michael Dixon.

Inside the historic London landmark museum they met donors and children as well as taking a peek at some of the exhibits on show, including a preserved common octopus collected by Darwin in 1832, a first copy of On The Origin of Species, and a collection of wasps he made on The Beagle and other voyages. 

 The outing comes a day after Clooney's dramatic intervention, in which he compared Meghan's struggles to those of the late Princess of Wales. 

Speaking at an event in Los Angeles this week, Clooney, 57, claimed that history was repeating itself in the case of Meghan and Diana, warning: 'we've seen how that ends'. 

After laughing off a report suggesting he would be chosen as godfather to Harry and Meghan's baby, Clooney said: 'They're just chasing Meghan Markle everywhere, she's been pursued and vilified.