The 21-year-old British star – who wed US musician Max Drummey in August 2008, before divorcing him just seven months later – will reportedly tie the knot with movie director Eli Roth in a New York rooftop ceremony in January.
It will be a traditional Jewish service in keeping with Eli's faith.
A source close to Peaches – whose father is Boomtown Rats singer Bob Geldof – said: "They are confident this is the real deal.
"They want a wedding on a New York rooftop and plan to invite about 50 friends including Quentin Tarantino.
"Apart from the trendy Manhattan venue it will be a traditional Jewish ceremony in keeping with Eli's family faith.
"They have been trying to keep it a secret."
Friends of the couple believe Peaches and the 38-year-old moviemaker will want to have children soon after marrying.
The source added to The Sun newspaper: "We wouldn't be surprised if they started a family together very soon."
Speculation is now rife Peaches will have to convert to Judaism so the couple can tie the knot in a traditional service.
Peaches previously admitted she didn't expect her first marriage to last.
She said: "I'm realistic, you can't ignore divorce rates. Every friend of mine has parents who are divorced. I didn't go into it with Max thinking, 'This is going to last forever,' but I did go into it thinking, 'I love him right now and I know that I'll continue to love him for a long while.' "