"It's going to completely redefine the game, and everybody is going to be waiting and watching to see what exactly President Trump does, but it will be his own platform," Miller said.
Miller, a spokesperson for Trump's 2020 re-election campaign, wouldn't go into detail about the new platform but predicted the former president will attract "tens of millions" of new users to his online presence.
Asked if Trump was going to create the platform himself or with a company, Miller said: "I can't go much further than what I was able to just share, but I can say that it will be big once he starts.
"There have been a lot of high-power meetings he's been having at Mar-a-Lago with some teams of folks who have been coming in, and ... it's not just one company that's approached the president, there have been numerous companies.
"But I think the president does know what direction he wants to head here and this new platform is going to be big and everyone wants him, he's gonna bring millions and millions, tens of millions of people to this new platform."
Trump was permanently banned from posting on Twitter after January 6, when his supporters stormed the US Capitol building. He was accused of inciting the violence during a speech to a crowd on the National Mall shortly before the rioting began.
In the aftermath of the attack, Trump was also suspended from Facebook and Instagram.
"After close review of recent Tweets from the @realDonaldTrump account and the context around them — specifically how they are being received and interpreted on and off Twitter — we have permanently suspended the account due to the risk of further incitement of violence," Twitter said in a January 8 statement.
Twitter executives said in February that the ban would stand.
"When you're removed from the platform, you're removed from the platform," Twitter CFO Ned Segal told CNBC on February 10. "He was removed when he was president and there'd be no difference for anybody who's a public official once they've been removed from the service."
