Ashlee Simpson Says Jessica Has Plenty of Time Before Giving Birth

Ashlee Simpson poses on the red carpet during the opening of Marquee Nightclub at The Star on March 30, 2012 in Sydney, AustraliaCredit: Don Arnold/WireImage.com

Despite Jessica Simpson's super-pregnant state, sister Ashlee Simpson isn't worried about missing the birth of her first niece.

On Thursday, the star, 27, jetted to Australia to celebrate the opening of Marquee, The Star, Sydney in Sydney Australia. At the event, she was overheard responding to a reporter's question about Jessica giving birth while she is down under.

"I have plenty of time," Ashlee answered. "And I'm going home [today] so it will be fine." (At the event Nick and Vanessa Lachey, Joe Jonas, Kellan Lutz, Wilmer Valderrama and Minka Kellywere also in attendance.)

Last week, Jessica was overheard telling a shopper at Fred Segal that her first child with fiance Eric Johnson still has a few weeks left in the oven.

"Only one month to go!" the Fashion Star mentor, 31, said. "I can't wear heels anymore. I tried, but it was too hard. Wearing heels is like a religion to me, so it's tough!"