"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 said via a statement released to People magazine.

The 45-year-old Bridget Jones's Diary star caused a social media storm after walking the red carpet at the Elle Women in Hollywood Awards looking unrecognisable.

While she acknowledged her looks had altered, she made no mention of plastic surgery.

"People don't know me in my 40s. People don't know me [as] healthy for a while. Perhaps I look different. Who doesn't as they get older?! Ha. But I am different. I'm happy," she said.

"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."

After being dumped by her husband, country singer Kenny Chesney, after just 128 days of marriage in 2005, Zellweger – one of Hollywood's most in demand actors throughout the early noughties – retreated from public life and acting.

"I just needed to put acting aside. I needed to sit still and not to worry about the dresses and the hair and the travel and the interviews. I was going through huge life changes at the time. I wanted to stop and be a girl for a while," she said.

She has since found love with guitarist Doyle Bramhall II and is more content behind the scenes producing and directing films.

"I did work that allows for being still, making a home, loving someone, learning new things, growing as a creative person and finally growing into myself."