Their adventure began 10 years ago when they filmed the first Iron Man movie together.
And to mark the anniversary Gwyneth Paltrow, 45 and Robert Downey Jr.,52, posed for a cute selfie from set as they embark on the fourth installment of the Avengers franchise together.
The black and white image sees Gwyneth, who plays Pepper Potts getting a kiss from Robert, who plays Tony Stark (Iron Man).
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Gwyneth Paltrow and Robert Downey Jr. cuddled up for a selfie on set of the fourth Avengers movie on Friday
In the caption the Goop founder wrote: ‘Ten years of #pepperony’ combining the names of their two characters.
Gwyneth shared more snaps from set earlier this week including a selfie showing her with long strawberry blonde wig while getting into character as Stark’s personal assistant.
‘Waiting to go on set’: the mother-of-two captioned the short selfie clip of her with her hair an makeup done.
In a second story she posted to her page Gwyneth got a foot massage from a therapist she claimed to have stolen from co-star Robert Downey Jr.
In the clip she asks the doctor: ‘Is my chi stagnated?’ to which the man responds ‘your chi is very good, you are healthy’
‘Am I healthier than Robert?’ the actress cheekily inquired but cut the video before his reply could be heard.
Eagle-eyed fans noticed that Gwyneth was wearing a motion-capture suit as she had her feet rubbed.
The sight prompted rumors online about the future of Pepper Potts, with fans asking why Stark’s assistant, who is normally based in an office, would need the visual effects.
Last month Chris Hemsworth, as Thor and Downey Jr (Iron man) were photographed on the set in Atlanta, Georgia as well as Tom Hiddleston in character as Loki.
Relaxed: In a second story she posted to her page Gwyneth got a foot massage from a therapist she claimed to have stolen from co-star Robert Downey Jr.
The untitled Avengers film will be released on May 3, 2019.
The sighting came days after Downey Jr confirmed he was a part of Avengers 4 with an Instagram photo; reprising his role as Tony Stark/Iron Man.
The snap showed Stark’s much smaller and more padded director’s chair in front of three others labelled Scott Lang, Natasha Romanoff and Steve Rogers.
Robert, 52, captioned the cryptic photo: ‘New flick, new short chair,’ explaining the reason for the different chair in the hashtag #lumbarsupport along with #marvel.
Marvel fans will know that the three names on the chairs are the alter egos of Ant Man, played by Paul Rudd; Black Widow, played by Scarlett Johansson; and Captain America, played by Chris Evans.
Filming on the superhero epic began back in August. The moment was marked by directing brothers Joe and Anthony Russo with an equally cryptic photo of a gloved hand, captioned: ‘Beginning the end.’
Meanwhile Gwyneth is reportedly engaged to boyfriend of three years Brad Falchuck.
The actress is a busy mom to two, having finalised her divorce from ex Chris Martin in 2014 after over ten years of marriage.
‘Infinity Trinity’: The actress is pictured with Downey Jr and Favreau aka Happy Hogan in August