The former One Tree Hill star grew up receiving kind words about her bright smile and when she realised it had been a while since someone had noticed, she decided it was time to do something about her fading pearly white teeth.

Bush, who is now a paid spokesperson for Philips, says, "I've always been really obsessed with my teeth because they're enormous and I have this mouth that becomes a big smile, and for years people would ask me how I whitened my teeth and I was like, 'Well, I don't'.

"And recently, because we do these 16-hour days on (TV show) Chicago P.D. and I'm pounding coffee all day long, I realised people weren't asking me that question anymore and I was like, 'Oh dear'.

"I've always been taking care of my oral health with Philips Sonicare and so I called them, because I'm always talking to them about the new toothbrushes coming out... I asked them, 'How do I deal with repairing the damage I've done to my teeth with all of this coffee and all of this red wine that I like to drink after work?' And they talked to me about Philips Zoom! and it's the easiest treatment... and you can go eight shades whiter.

"Suddenly people are asking my how I whiten my teeth again."