Credit: Michael Tran/FilmMagic

The countdown is on for Spencer Grammer!

The 27-year-old former Greek actress is expecting her first baby with husband James Hesketh on Saturday, but she still found time to support her dad, Kelsey, at the premiere of his Starz series, Boss, Thursday in L.A.

But the TV star is in no rush to have her little one. In fact, she anticipates she'll be overdue.

"Saturday I'm due, but I think it's going to be a week later," she told Us Weekly Thursday. "A lot of women don't deliver on their delivery date. A lot of people I know this year delivered early, so a 40 week [pregnancy] is never really 40 weeks!"

When it comes to preparing their home for their newborn's arrival, Grammer says she and hubby Hesketh are taking things slow.

"We painted [the nursery] months ago so there are no toxins and stuff and we have toys and a co-sleeper," the first-time mom-to-be explained. "We kind of were like, 'we'll just do one phase at a time.' He'll need a crib in a few more months."

Grammer played coy when asked if her dad, Kelsey, will expand his family with new bride Kayte Walsh.

"He loves babies. Doesn't everyone love babies?" she demurred of her father, who wed Walsh in February. "You know. All in good time."