Meghan, 35, met up with Piers after she spent a day watching tennis and drinking champagne in the Royal Box at Wimbledon. Piers says their conversation gave him 'a pretty good insight into the new global object of Royal girlfriend frenzy.'
Harry last week hit out at the 'abuse and harassment' Meghan has endured, including 'sexism and racism' from 'social media trolls'.
But, as Meghan told Piers, this is not entirely new territory, as she was bombarded with hate messages when her character in the US drama series Suits, Rachel Zane, cheated on her boyfriend in the show. She said: 'People wanted to kill me! Not Rachel... ME. I never knew there were so many emojis with guns and knives. It was very unpleasant. Fortunately, Rachel got back on her pedestal and it stopped.'
Meghan said she supported gun control measures in the US, and wished more people would take a stance to try to stem 'so many needless deaths' - as Piers did on his CNN show. She also spoke about her mixed race upbringing, saying: 'My dad's Caucasian, my mother's African-American, so I'm half-white, half-black. It caused me a lot of confusion when I was young because it's not easy to be ethnically ambiguous in America. But I learned to embrace being a mixed-race woman.'
And Meghan revealed some more obscure secrets about herself - such as the fact that she is a trained calligrapher who wrote the invitation cards and envelopes for pop singer Robin Thicke's 2005 wedding.
In another tip for Harry, she said: 'There's still something incredibly romantic and special about a guy writing to a girl and putting pen to paper rather than emailing it.'
Meghan was also a 'briefcase girl' on the American version of TV quiz show Deal Or No Deal. 'I cringe when I think about it now,' she said. 'But it paid the rent.' On the show, she was forced to 'stand for hours in very cheap, very high heels waiting for someone to pick me'.
So now that Harry has picked her, what does Piers think of the new Royal consort?
'She's got beauty, brains, charm, and a great sense of humour,' he says. 'Meghan Markle is perfect princess material.'
Prince Harry watched England play rugby yesterday with a stunning date - but it wasn't his new girlfriend Meghan Markle.
Despite speculation that Twickenham would provide the venue for his first public appearance with Suits star Ms Markle, the Prince instead sat next to the striking Princess Charlene of Monaco - a former Olympic swimmer for South Africa and the wife of Prince Albert.
Harry, 32, arrived alone to lay a poppy wreath outside the stadium in South-West London ahead of England's autumn international game against South Africa. The home side won a rain-soaked match 37-21.
Bookies had slashed the odds that the Prince and the American actress would be seen together at the 82,000-seater stadium.
The pair have been dating for several months but have not been seen in public together. On Thursday morning, Ms Markle was seen walking into Kensington Palace, West London, where Prince Harry has a home.
The Prince took a previous girlfriend, Cressida Bonas, 27, to an England versus Wales match in 2014, sitting with her in the stands.
Prince Harry has confirmed he's dating American actress Meghan Markle - a 35-year-old divorcee from LA, who plays sexy, whip-smart paralegal Rachel Zane in Suits, a US TV law drama that's one of my favourite shows.
A year ago, I started following its stars on Twitter, including Meghan. She promptly sent me a Direct Message: 'Well hello there - thanks for the follow. Big fan of yours!'
Over the next few months we exchanged regular amusing debate about various storylines and she even emailed me future episodes not yet available in the UK.
In late June, she messaged me to say: 'I'm in London for a week of meetings and Wimbledon, would love to say hi!'
I suggested my local pub in Kensington. Meghan came straight from the Royal Box at the tennis, giggling from 'a little too much champagne...' 'Serena Williams sends her love,' she said. 'You're very popular, it turns out. Get you.'
One of the locals spluttered in shock, at both parts of that statement.
I ordered a pint of bitter, Meghan had a dirty martini and we chatted for 90 minutes or so. Long enough for me to get a pretty good insight into the new global object of Royal girlfriend frenzy.
She's strikingly beautiful, intelligent (she has two degrees, in theatre and international relations) and has a fun, feisty personality that flits easily between serious and frivolous subject matters.
We discussed her biracial upbringing and then we talked guns. 'I've enjoyed living in Canada [where Suits is filmed] for the past five years, without Rambo & co,' she said.
'People say it's not the guns but mental illness, to which I say, so then why give mentally ill people legal access to buy guns? It's staggering. So many needless deaths.'
Concerning the period of time last year Meghan's character Rachel briefly became a hate figure, Meghan said: 'There's a great quote from the artist Georgia O'Keeffe that resonates with me: "I have already settled it for myself so flattery and criticism go down the same drain, and I am quite free."
Judging by Prince Harry's statement, this philosophy has been severely tested in recent days.
'Did you always want to be an actress?' 'No. As a kid, I wanted to be either President of the United States or a news broadcaster like you'
Meghan's a passionate campaigner for women's rights and told me a fascinating story that says a lot about her spirit.
'When I was 11, I saw this ad for dish soap powder that said: 'Women all over America are fighting greasy pots and pans.'
'I was so angry. I couldn't understand why it didn't say men as well. My parents always told me if I believed something was wrong, I should try to fix it. So, I wrote to all sorts of people including Hillary Clinton and the soap's manufacturers Procter & Gamble, demanding they change it. It worked. They altered the wording from 'women' to 'people'.'
She later left in an Uber for dinner in Mayfair but was spotted in Soho House next night with Prince Harry.
I'm not surprised he's fallen for her, or that he's so ferociously protecting their relationship.
Harry, ignore all the poisonous rubbish you're reading or hearing about her. Meghan Markle is perfect princess material. Just put any proposal in writing.
WHAT MEGHAN SAID NEXT...
On being 'mixed race'
I'm half-white, half-black. It caused me a lot of confusion when I was young because it's not easy to be ethnically ambiguous in America.
On death threats
'People wanted to kill me! Not Rachel... ME. I never knew there were so many emojis with guns and knives. It was very unpleasant'
On her embarrassing TV moment
In was a briefcase girl on Deal or No Deal... I cringe when I think about it now, but it paid the rent.
... and on dating again
I've got a few guys being a little... persistent! I'm just out of practice with the dating scene.
