Piers Morgan mocks Prince Harry and Meghan Markle as they welcome baby girl.

Piers Morgan has mocked Prince Harry and Meghan Markle after they welcomed their baby daughter Lilibet Diana Mountbatten-Windsor.

The former Good Morning Britain host, who is one of the couple's most vocal critic, took to Twitter after they announced on Sunday that earlier this week they had welcomed a baby girl.

The baby girl has been named Lilibet, Lili for short, after the Queen's family nickname but she will be known as Lili, and Diana after Harry's later mother.

And Piers said he wasn't going to tweet about the baby news, as he joked he was respecting the couple's privacy.

Piers tweeted: "To those asking for my reaction to the new royal baby, I am respecting her parents' constant pleas for privacy and declining to comment."

Piers mocked the couple on Twitter.

He was referring to the couple saying they stepped down as senior royals to live more private lives, but then went on to give endless interviews.

Harry and Meghan's baby is a little sister for their son Archie, who was born in 2019, and a new cousin for Prince George, Princess Charlotte and Prince Louis.

A statement from the couple's press secretary said: "It is with great joy that Prince Harry and Meghan, The Duke and Duchess of Sussex, welcome their daughter, Lilibet "Lili" Diana Mountbatten-Windsor, to the world.

"Lili was born on Friday, June 4 at 11.40am in the trusted care of the doctors and staff at Santa Barbara Cottage Hospital in Santa Barbara, California.

"She weighed 7lbs 11oz. Both mother and child are healthy and well, and settling in at home.

"Lili is named after her great-grandmother, Her Majesty The Queen, whose family nickname is Lilibet.

"Her middle name, Diana, was chosen to honour her beloved late grandmother, The Princess of Wales.

"This is the second child for the couple, who also have a two-year-old son named Archie Harrison Mountbatten-Windsor.

"The Duke and Duchess thank you for your warm wishes and prayers as they enjoy this special time as a family."

It comes after Piers hit out at Meghan yet again in an interview with 60 Minutes Australia in which he called her a "liar".

He said on the show: "I didn't know this at the time but Meghan Markle had complained to my boss at ITV on the Monday night.

"It was demanded I apologise for disbelieving her otherwise I would have to vacate my chair.

"I thought there was hypocrisy, I thought there were downright lies coming out in the interview.

"I saw my job to hold them to account like I would to a government minister and for doing that, within 36 hours I had to leave the job."

He added: "You're not allowed to have strong opinions about things, you're not allowed to disbelieve a liar like Meghan Markle.

"I'm sorry to call her that but she tells lies. We've demonstrated and proven that."

Piers had quit Good Morning Britain after 50,000 people, including Meghan, complained about his comments about the Duchess of Sussex.

He had hit out at the couple's interview with Oprah Winfrey, which aired earlier this year, and said he didn't believe anything Meghan said.

This included Meghan's brave admission that she had suffered suicidal thoughts and her claim that she'd been refused help from the Royal Family.