updated 04/24/2011 AT 11:00 AM ET
•originally published 05/03/2011 AT 2:20 PM ET
Kings of Leon singer Caleb Followill says he doesn’t know the exact date of his wedding, but he seems certain that he will marry his Victoria’s Secret model fiancée Lily Aldridge in May.
“You have to ask Lily [about the wedding date]. She won’t tell me. I think it’s somewhere between May 10 and May 20, but she won’t tell me because I have a big mouth,” Caleb told PEOPLE recently at the Tribeca Film Festival premiere of his band’s documentary, Talihina Nights: The Story of Kings of Leon.
Caleb’s bandmate brothers Nathan and Jared Followill, however, are more forthcoming when it comes to the specifics of the wedding.