"It's true," James told The Associated Press on Thursday.
No wedding date has been announced.
James and Von D began dating over the summer after his very public split from Oscar-winner Sandra Bullock.
The 41-year-old biker-businessman and reality TV star called Von D his best friend. Von D, whose real name is Katherine von Drachenberg, says James is the one. The 28-year-old stars on the TLC reality show "LA Ink."
The engagement was first reported Thursday by People.com.
James told the magazine, "2010 was actually the best year of my life because I fell in love with my best friend. An amazing woman who stood behind me when the world turned their backs."
James and Bullock were married for five years. Their marriage collapsed amid allegations of infidelity just after Bullock won an Oscar for her role in "The Blind Side" in March, 2010.
James apologized publicly to the actress and his three children from previous relationships for causing them "pain and embarrassment beyond comprehension."
He later told ABC's "Nightline" that he was the most hated man in the world for capping off Bullock's career high with a deeply personal low.
The couple separated in March and their divorce was finalized in June.
James began professing his love for Von D on Twitter earlier this month, writing on Jan. 9: "I have Never Felt so Loved! I'm The Luckiest (man) in the World!"
Von D posted on the micro-blogging site Thursday that she is "overwhelmed with joy."
