Patrick J Adams, lead in the TV series, announced he and Troian Bellisario would be hosting a game night livestream. The event is in support of the Senate runoffs in Georgia on January, and will raise funds for the Democrats ahead of the crucial election.
Mr Adams sparked excitement in royal fans when he said a “very special guest” would join the event.
Posting on Twitter, he said: “We have a very special guest joining us tonight. You’ll need to tune in to find out who, though!”
He added later: “All I’ll say is our special guest knows the ins and outs of both law and politics…”
Meghan played Rachel Zane, who was Mr Adam’s love interest, on Suits from 2011 to 2018.
READ MORE: Meghan Markle’s ‘determined’ speech shows ‘astonishing differences’ with Prince Harry
Mr Adams previously said to the Radio Times he was scared to talk to the now-Duchess after she married Prince Harry.
He said: “Quite frankly, I think I’m intimidated. I have no doubt I could pick up the phone and call her at any moment, but I don’t know what I would say.
“After our children were born, there were some texts sent and gifts sent, but I guess I’m a little scared. I think it’s pure fear.
“I guess I’m scared about the idea of breaking through whatever walls exist to have that conversation.”
Others raised eyebrows about the Duchess’ rumoured appearance, with some taking issue with the political aspect of the livestream.
One user said: “I used to like Suits, but if Game night becomes another surprise visit from Mrs Attention Seeker I won’t be watching.”
Another added: “I didn’t mind Markle then as she wasn’t the phony humanitarian narcissist we now know her to be.”
But a fan of the royal said: “It would be very appropriate for Meghan to support this cause. So I am rooting for her to say hello.”
Meghan was savaged earlier this year by royal experts for urging American’s to vote in the US election.
The Duchess made a series of online appearances at “get out the vote” events urging women to cast their ballot, but did not make a specific endorsement of any candidate.
After the Duchess and Harry appeared in a Time 100 video, a royal aide said to day Times: “The family are all wringing their hands, thinking, ‘Where is this going?’ The feeling is it’s a violation.”
Piers Morgan, host of Good Morning Britain, said in August: “The Queen must strip the Sussexes of their titles. They can’t remain as royals & spout off about foreign elections in such a brazenly partisan way.”