There is one person who isn't excited for the upcoming royal wedding between Prince Harry and Meghan Markle - her own brother.

In a handwritten letter addressed to Prince Harry, Markle's estranged half-brother, Thomas Markle Jr, criticised his sister and warned Prince Harry it is not "too late" to call off the wedding.

In the letter shared with In Touch magazine, the 51-year-old wrote: "As more time passes to your royal wedding, it became

very clear that this is the biggest mistake in royal wedding history. ”

According to Thomas, who has not seen his half-sister since 2011, it was the fact that the American actress did not invite her family to her upcoming royal wedding, instead inviting “complete strangers," that struck a nerve with

her half-brother, who asked: "Who does that?"

In the letter, Thomas blames Hollywood fame for allegedly changing Markle, who starred on Suits until recently.

"It's very apparent that her tiny bit of Hollywood fame has gone to her head, changing her into a jaded, shallow, conceited woman that will make a joke of you and the royal family heritage, ” he wrote.

This isn't the first time Markle's half-brother has spoken out against his sister.

Last month, Thomas told the Daily Mirror that

Markle has "forgotten her roots" and likes to portray herself as a "people's person."

But Thomas insists he is not hurt over not being invited to the upcoming wedding on 19 May 2018. "I'm not bitter, just baffled," he told The Mirror. "It's hurtful given how close we once were."