Some of our favorite stars gave us pretty contagious smiles this week, setting the tone for a happy Spring. Kate Middleton broke out in giggles when she spoke with Irish Guards at a St. Patrick's Day event, and Scarlett Johansson  lit up when she and Chris Evans brought their Captain America premiere parade to London. Meanwhile, Ryan Reynolds  made our hearts stop with his smoldering stare and semipopped collar, and Charlize Theron  had us wondering when her bikini photo shoot snaps will be released. Keep reading to see all that and more!
Source: Getty  and FameFlynet 
Kate Winslet got a star on the Hollywood Walk of Fame  in LA on Monday afternoon!
Charlize Theron struck sexy poses  throughout her bikini photo shoot in Key West, FL.
Michelle Obama had a blast  playing ping-pong on Thursday during her action-packed stay in Beijing.
Shailene Woodley and Theo James shared a sweet moment  at Thursday's screening of Divergent at NYC's Hearst Tower.
Scarlett Johansson walked the red carpet  with Chris Evans at the UK premiere of Captain America: The Winter Soldier in London on Thursday.
On Tuesday, Ryan Reynolds paid a visit to the set of The Age of Adaline  in Vancouver, where his wife, Blake Lively , has been filming her latest project.
Meanwhile, Blake Lively made a very special friend  on Monday when she greeted a dog on the set of her new project in Vancouver.
Minnie Mouse looked superpsyched to see Katie Holmes  at Walt Disney World on Sunday.
Kate Middleton had a good laugh  as she participated in an annual St. Patrick's Day tradition of visiting the Irish Guards in Aldershot, England, on Monday.