It's the Hair in Review (HiR) for 4.20! A weekly recap of the past week in hair. 
It looks like this week was all about celebs making some serious hair changes, most notably, always sporting strict blonde hair, Gwyneth Paltrow embraced the ombre trend.
Rooney Mara went from the girl with the dragon tattoo to unrecognizable with extensions from Great Lengths.
Actress Jennifer Morrison, from Once Upon a Time, goes deep gorgeous (yes, we like!) red, a major switch from her trade mark blonde.
And not so surprising, Katy Perry went from blue hair to purple hair. Oh Katy! You're so edgy. 
Also in the news: an adorably cute bald rat grows hair, thanks to Japanese Scientists; thus further paving way for a possible cure in hair loss for humans. Okay that rat is not so adorable. American Salon Teen Correspondent Emily tried out Hair Flairs Color Rubs, temporary color that rubs directly onto the hair. 
Emily chose pink, blue, orange and yellow because they are some of her favorite colors! Stay tuned for more from emily in later HiRs, and maybe you'll even run into her at IBS!
See you this weekend at the International Beauty Show!
Happy Earth Day 2012!