Speaking to close pal Karl Larsen on the show's debut, Thomas also said he is ready to give evidence against Meghan in a court case brought by her half-sister Samantha, saying he would be "thrilled" to get Meghan and Harry into the courtroom.
“I would be more than happy to. I’ve been trying for almost four years to get to see my daughter and her ginger husband in a courtroom face-to-face," Thomas said.
“I’d be thrilled to defend my oldest daughter.”
Samantha, 57, is suing her Meghan for $75,000, claiming she lied about her to the authors of her controversial book Finding Freedom and during her TV interview with Oprah Winfrey.
Thomas suggested that Meghan would be wise to settle the case which was officially lodged in Florida last week, saying, “She can’t defend the things she said.”
"I'm standing up for my oldest daughter, Samantha. In this case, she should win because Meghan's book was full of lies about her. I would appear in a deposition in this case, if it came to it."
Michael Kump, who is representing Meghan, called the lawsuit "baseless and absurd" and a "continuation of a pattern of disturbing behaviour".
He added: "We will give [the lawsuit] the minimum attention necessary, which is all it deserves."
WATCH: Thomas Markle eager to meet Meghan and Harry even if it’s in court
Of Thomas' choice to kick off his controversial YouTube channel, co-host Karl said: "Tom wants to do it to put his thoughts out there from the horse's mouth.
“He wants to speak about how Meghan and Harry have affected his family. The chat will be no-holds-barred.
"He wants his truth to be out there, just like Meghan's truth came out a year ago in her Oprah Winfrey interview.
"He also wants to speak about other things in the news, too."
