Anna Torv and Joshua Jackson

Last week's midseason premiere of Fringe left fans with one very important question: Is alternate-Olivia (Anna Torv) pregnant with Peter's baby?

After chasing the Observer through the streets, Peter (Joshua Jackson) came face to face with the man who once saved his life, but now was seemingly trying to kill him to test Walter (John Noble). "It must be very difficult," the Observer said. "Being a father."

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Wait. What? Peter is a father? While the interpretation of "father" could apply to Peter or Walter, since he was the patriarch being tested, we posed the possibility of Alt-Olivia being pregnant to Joshua Jackson.

"You know as well as I do that I can't tell you that," Jackson says coyly. "It's Fringe. We don't drop like lines that [for no reason]."

This season, Peter thought he was falling in love with this universe's Olivia, with whom he's been working over the last few years. But it was Alt-Olivia (or Bolivia, as the cast and crew call her), who was using him to infiltrate the Fringe Division. Once the truth came to light, Peter's world shattered as he realized he was falling for the wrong woman.

"I like to refer to Peter now as the dumbest smart man on the planet," Jackson says. "Olivia is getting a lot of sympathy, but Peter, with the best of intentions, [screwed]-up huge. He didn't know. It's not like he stepped out on his girlfriend ... To his credit, Peter has been a mensch, at least, about admitting what went on."

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"They wrote, and hopefully we'll perform in a nicely grown-up way, the fallout of the 'Peter slept with Bolivia thing' with Olivia," Jackson says. "These are two grown-up people who are trying to deal with a circumstance that nobody on our planet has literally ever dealt with. I was pretty disappointed with how stupid Peter was earlier in the year, so I like that he's being a man about this."

Peter will now grapple with whether he's truly in love with Olivia, or if his heart lies with Bolivia. "There's no easy answer to that," Jackson says. "Only on Fringe do you have problems like this."

Fringe airs Friday at 9/8c on Fox.