It's the first week of 2015, and just like us, Hollywood's hottest are getting back in the groove of their regular workout routines. With chilling temperatures all over the country, making time for a workout this weekend might seem like a bit of a stretch. Let stars like Dakota Johnson [1], Reese Witherspoon [2], and more motivate you to leave the comfort of your nest and hit up the gym!

Reese Witherspoon

With a pink yoga mat in tow, Reese Witherspoon [3] hit up a yoga class after her holiday travels.

Kendra Wilkinson

A fresh-faced Kendra Wilkinson stepped into her local Equinox for a workout with a water bottle in hand.

Britney Spears

Britney Spears [4] stepped out of a challenging dance rehearsal rocking a throwback crop top.

Dakota Johnson

50 Shades of Grey star Dakota Johnson [5] hit up a Pilates class in West Hollywood. She must be preparing for the release of her much-anticipated film!