"It's going really well," the 30-year-old Hitchcock star told David Letterman.
When the host inquired whether the two are best friends, Biel replied: "Oh, we are BFFs for sure."
Biel and Timberlake tied the knot Oct. 19 at the Borgo Egnazia resort in southern Italy, welcoming 100 guests including close pals Jimmy Fallon, Andy Samberg, Timbaland and Biel’s 7th Heaven costar Beverley Mitchell. Alas, nobody from N'Sync made the cut.
The photos sold to People in the U.S. for a reported $300,000, and to OK! in Europe for an undisclosed amount.
"We wanted to keep it as much of a secret as we could at least up until it actually happened. So I kind of got really obsessed with this sort of crazy CIA operative scheme I put in play right before the wedding," Biel explained to Letterman, stopping short of giving away the full details.
The conversation then turned to Biel's traumatic encounter with two naked men at an Austrian spa ("not just naked but balls on wood, Dave, that's not OK").