Hollywood pals turned out for Hudson's birthday party in Pacific Palisades, California, and the Big Little Lies star, 43, was there with husband Jim Toth.
In fact, Reese is always up for A-list fun.
She attended Jennifer Aniston's star-studded 50th birthday celebrations in February 2019 and fell down while leaving the bash.
Back then, the Oscar winner surprised onlookers by taking a tumble in her high heels.
Reese also donned disco duds for a 1970s-themed party in March.
For Kate's party, however, Reese held Toth's hand while wearing a demure floral frock.
Scroll through Radar's gallery for more on Reese making the celebrity party scene once again!
Kate The Great
Reese paid tribute to her pal Kate on her Instagram stories on Friday, ahead of attending her birthday party. She posted a photo of the Almost Famous actress, writing, "Happy Birthday Kate Hudson. I've known this beauty since she was 12 years old! Has always been the most optimistic and joyful."
Ready For Fun
The Legally Blonde star's image was once squeaky clean but now she's a regular at booze-soaked bashes. Reese's friend Kate's mom Goldie Hawn and stepdad Kurt Russell also wished Hudson a happy 40 years. Kate welcomed daughter Rani Rose in October by baby daddy Danny Fujikawa.
Did the blonde dynamo enjoy herself a little too much at Jen Aniston's 50th birthday party on Feb. 9? She fell down a flight of stairs! Then at a March disco bash, Reese shared photos of herself partying with buddy Greg Kinnear.
Not Walking Line
Reese's embarrassing incident at Jen's birthday party began when the actress looked red-faced as she left. She grabbed a glass handrail for support as she and such Hollywood stars as George Clooney, Sandra Bullock, Courteney Cox, Gwyneth Paltrow, and Ellen DeGeneres left the bash at the Sunset Tower hotel in West Hollywood. She suddenly lost her balance.
Reese's husband Jim was right by her side at Kate's party this weekend. In 2013, Witherspoon and Jim were both arrested for disorderly conduct in Atlanta, Georgia. She later pleaded no contest to obstruction and was required to pay court costs. Toth pleaded guilty to misdemeanor DUI, was ordered to perform 40 hours of community service and attend an alcohol education program, plus pay a $600 fine.