AsiaOne via The Straits Times mentioned that the American actress turned up at ELLE Women In Hollywood Awards in Los Angeles on Monday with tighter skin and a pair of eyes that looks very different.
In fact, according to Metro, Zellweger was nearly mistaken for Cameron Diaz at the event. Some even say she looks like American actress Robin Wright Penn.
The drastic change prompted speculations of plastic surgery even though the 45-year-old has never admitted to going under the knife.
According to plastic and cosmetic surgeon Alex Karidis of London's Karaidis Clinic, in an interview with MailOnline, the smaller distance between the brow and her eye might be caused by an upper eye lift.
However, another expert, Dr Yannis Alexandrides, claims that Zellweger may have gone through a non-surgical treatment called Thermage instead - a procedure that "uses radio frequency to tighten elastin fibres and stimulate collagen and gradually improves the quality of the skin and tissue over a period of six months".
The actress also responded to comments on questions about her new look: I'm glad folks think I look different! I'm living a different, happy, more fulfilling life, and I'm thrilled that perhaps it shows," she told People Magazine.
She called the discussion about her appearance "silly" and said that she is responding to the reports as "it seems the folks who come digging around for some nefarious truth which doesn't exist won't get off my porch until I answer the door."
"My friends say that I look peaceful. I am healthy. For a long time I wasn't doing such a good job with that. I took on a schedule that is not realistically sustainable and didn't allow for taking care of myself.
"Rather than stopping to recalibrate, I kept running until I was depleted and made bad choices about how to conceal the exhaustion. I was aware of the chaos and finally chose different things."
She added that people don't know her in her 40s and healthy.
"Perhaps I look different. Who doesn't as they get older? I am different. I'm happy," she told the magazine, explaining that while some may not recognise the new Renee, she wants to let them know that she is comfortable in her own skin.