Maybe later this year The square, cushion-cut diamond engagement ring that Biel happily showed off on the red carpet at the Met Gala earlier this month was designed by her 31-year-old beau, she said. "It looks like it is an antique ring, but [it's not]. He designed it to give that impression." And if Biel has her wedding dress selected (it's rumored that Elie Saab will make her a custom gown), she isn't spilling any details. "If you want to know the truth, I have not yet found the dress," Biel said. As for whether or not they'll soon join the Hollywood baby boom, Biel replied, "I don't know... I am a person who let things happen naturally. I was told that after [turning] 30, a woman begins to hear the ticking of her biological clock. I have not had that feeling." Biel and Timberlake's engagement party took place on Saturday at the Los Angeles home of her stylist, Estee Stanley. There were 100 guests in attendance from Timberlake former boy bandmates Lance Bass and JC Chasez to Ellen DeGeneres and Portia de Rossi. Biel's parents were there as well. "Jessica and Justin were mingling both separately and together throughout the party," an insider told Us Weekly. "Jessica seems to be very close with Justin's friends and vice versa. You can see that they have been dating for a long time and really know each other's friends and family well. The party was a fun celebration and a preview of what's to come with the wedding." Biel and Timberlake are expected to marry later this year.