The British hunk will front the sketch show with Bad Bunny as the music guest.
This will be Page's "SNL" debut while Bad Bunny appeared in a remote production of the NBC show in April (20), alongside Keenan Thompson.
Meanwhile, it has been revealed Rege-Jean has a secret girlfriend.
The 31 year old, who picked up an army of new fans with his portrayal of the hunky Duke of Hastings in the steamy Netflix show, is reportedly smitten with writer and part-time soccer player Emily Brown.
According to the Mail on Sunday newspaper, the couple shares a home together in North London. They were recently spotted embracing in the street before he flew to New York for a week of "Saturday Night Live" rehearsals.
Page has been tipped to take over from Daniel Craig as the next James Bond, with his "Bridgerton" co-star Adjoa Andoh among those backing him to get the role, "I think the thing with Rege is, he is beautiful. Don't tell him I said that. He is very smart, he is a fantastically funny, sharp actor, so he could take on any role you give him really. Annoyingly, he could. He would be a marvellous James Bond if they ever decided to go that way, no doubt at all."