But all that travelling, combined with caring for her twin babies, did nothing to dampen to Hollywood glamour exuded by Jennifer as she arrived in London this week.
The 40-year-old beauty made a real impact on the pink carpet in Leicester Square as she worked her curves in a one-sleeve Lanvin dress and black satin Ferragamo heels.
With her hair swept up on top of her head, the actress ensured all eyes were on her as she spent time with her British fans, who turned out in droves, taking the time to sign autographs and pose for photographs.
Also at the screening was Jennifer's co-star, Australian actor Alex O'Loughlin and the rom-com's director Alan Poul.
The film, which is due for release in the UK on May 7, stars the New York-born brunette as pet store owner Zoe who tried artificial insemination to have a baby after failing to find the right man.
It's only after finding out IVF has been successful and that she is pregnant, that she meets the guy of her dreams, played by Alex.
Having experienced pregnancy herself – fraternal twins Emme and Max were welcomed into the world in February 2008 – Jennifer was determined to stay true to the experience.
Speaking at the premiere, the Out of Sight star revealed: "There's a couple of scenes in the movie where I'm eating and pigging out and they didn’t put them in the first cut. – I was like 'Listen guys, this is extremely important for women.'
"'They need to see me pigging out. This is what happens when you get pregnant.'"
Jennifer, whose last film role was three years ago, also spoke about how much she enjoyed her long-awaited return to the movie industry.
"I had a two-and-a-half year maternity leave so it was good to get back to work," she said.
Click here to see the trailer for The Back-Up Plan.