It was just a small soiree with the likes of Jennifer Aniston, Nicole Ritchie, Kate Hudson and Matt Bellamy in tow. No biggie.
The famous pair - who announced their "separation" last March - have managed to remain on friendly terms, and the Coldplay frontman treated her to the intimate birthday bash at her Los Angeles home.
According to the New York Post, the star also invited some of Gwyneth's colleagues from her lifestyle newsletter, Goop, and some parents whose children attend the same school as their 10-year-old daughter, Apple, and their eight-year-old son, Moses.
As usual, a well placed "insider" confirmed the pair were genially swinging out of each other at the birthday bash, saying: "[Gwyneth and Chris] were very friendly to each other. It was like they're still best friends."
One person who was not there to join in the fun was Chris' rumoured girlfriend, Jennifer Lawrence.
But their relationship is still said to be going strong as they enjoyed a romantic ride/spin on a big wheel in Las Vegas on Friday.
A source said: "The cabins usually accommodate up to 40 people, but Chris and Jennifer booked a private one for some alone time."
We'll let your mind alone with that one for a while.
