Thomas Markle talked about the birth of Meghan Markle and Prince Harry's daughter Lilibet, and threatened to air his daughter's dirty secrets in an exclusive interview.

In a preview for his explosive "60 Minutes Australia" interview airing on Sunday, the retired Hollywood lighting director shared that he only learned about the royal baby's birth along with the general public. He did not get a phone call from his daughter but "heard it on the radio."

As to the hope of seeing his grandaughter Lilibet, Thomas says, "I'll be very disappointed that I don't get to hold my granddaughter."

When asked by reporter Tom Steinfort if he thinks his daughter still loves him, he reveals that he has not talked to Meghan since two days before she married into the Royal Family. He also pleads to be forgiven for that "one dumb mistake" he made in 2018, in which he staged paparazzi photos in Mexico leading up to the Royal Wedding.

He says he is still "confused" as to why their "great relationship" ended and still hopes to mend that broken relationship.

"I've made mistakes. I apologised a hundred times for it," he tells Steinfort and adds, "If I had done something terribly wrong, that would be fine, but I haven't."

The preview ends with the 76-year old threatening to air the Duchess of Sussex's dirty secrets. He says, "You want dirty laundry? First time I've discussed these things."

Thomas' interview comes days after Meghan and Prince Harry welcomed their baby girl Lilibet "Lili" Diana Mountbatten-Windsor on June 4. They announced her birth on June 6 and Thomas was among those who greeted the couple on their new bundle of joy.

"I am very pleased with the announcement of the safe and healthy delivery of my new granddaughter, and I wish her and her mother all my love and best wishes," he said in a statement.

Chances are slim that Thomas will get to see Lilibet and even Archie as Meghan has cut him off from her life. It is said that he has not even met Prince Harry personally. The duchess admitted in her Oprah interview in March that she felt betrayed when her father lied about staging those paparazzi photos.

Meghan Markle and Prince Harry
Prince Harry's wife Meghan Markle speaks of her heartache after learning of her father Thomas' betrayal in her interview with Oprah Winfrey Photo: CBS / Sebastien VUAGNAT