Gwyneth Paltrow attended her ex-husband Chris Martin's star-studded birthday bash.

Chris Martin and Gwyneth Paltrow (c) Instagram

Chris Martin and Gwyneth Paltrow (c) Instagram

The 46-year-old actress - who has two children, Apple, 14, and Moses, 12, with her former spouse - joined the likes of the Coldplay frontman's girlfriend Dakota Johnson and her mother Melanie Griffith, Julia Roberts and Sean Penn at his Malibu mansion for a celebration of his 42nd birthday on Saturday (02.03.19).

The Goop founder - who is now married to producer Brad Falchuk - took to Instagram to share a selfie with the 'Yellow' hitmaker with standing by a door with the number 42 painted on it, and gushed that "we love you so much".

She captioned the sweet post: "Happy Birthday CAJM.

"This is a special one. We love you so much. #42."

An insider said the bash was chilled out and that guests were serenaded by a mariachi band, whilst tacos were served from a cart.

The source told E! News: "It was a very laidback vibe with friends and neighbours dropping by in the afternoon.

"Some people walked over in the rain and nobody seemed to care. They had a mariachi band and a taco cart."

Chris - who split from Gwyneth in 2014, after a decade of marriage - was reportedly "bouncing" and "very energetic" as he celebrated with his showbiz pals.

The insider added: "Chris was in a great mood.

"He was bouncing around and very energetic."

A day earlier (01.03.19), Gwyneth marked her husband's birthday with a touching tribute, in which she hailed him as her "rock".

Alongside a selfie with the dark-haired hunk - who has teenagers Brody and Isabella with ex-wife Suzanne Bukinik - she wrote: "It's your birthday, but it's really feels like you are the gift. Not just to me, and to @izzyfalchuk and Brody, but to all of us who are fortunate enough to know and love you. You are my rock, my true north, my favorite person to eat with, to travel with. You are a true friend. You want only what is for the highest good. You always help me see what I can't. I am so happy you were born @bradfalchuk I love you so much. (sic)"