Entertainment Tonight Canada joins Leighton Meester on the set of her new Herbal Essences ad, as she lets us in on some secrets of the upcoming season of “Gossip Girl“.

“Gossip Girl” star Leighton Meester talks to reporters backstage at the 2010 Teen Choice Awards.

I recently spent the day holed up in a private suite of London’s Berkley hotel with Leighton Meester – aka Blair Waldorf (check out this week’s Grazia to read all about it).

For those of you that are fans of Gossip Girl, you’ll no doubt have a love/hate thing going on with Blair. On the one hand the uptight upper east sider is so machavelian, she makes Rachel McAdams in Mean Girls look like Mary Poppins. On the other hand there’s her immaculate buttoned-up  fashion, creamy skin, manicured brows, and hair  so shiny and perfect it would take the prize at Crufts. The later is evidently why she’s scored a lucrative deal with Herbal Essences.

According to her hair dresser Charles Baker Strahan, her mother used it on her as a child, he reintroduced her to it (she loves the smell), and the rest is history.

In real life Leighton is more Mary Poppins than Blair Waldorf; polite and agreeable -  accomodating our numerous requests to check out her makeup bag (her go-to buy is Laura Mercier’s tinted moisturiser), go through her London wardrobe (she lives for fierce shoes) and sniff perfumes in search of her new season favourite – Issey Miyake The scent fyi (see the video below).

Whilst Blair is perfectly groomed  Leighton is more tracky bottoms and bed-head hair. Blair is low carb, and low fat, whilst Leighton ordered soup and bread, with a side of chips!

Despite the differences, I did pick up a few Blairisms from my time with Ms Meester. One must wear heels at all times – hence why she says she always fits in time to have regular mani-pedi’s. ‘It makes you feel dressed,’ she tells me. Treat your hair like your skin and give it regular masks (Herbal Hello Hydration), and when it comes to anti-ageing procedures less is more and never say never.

Beauty advice to live by I think.

Glossip Girl x