By Karen Mizoguchi
November 04, 2017 at 10:30 AM EDT

Chris Pratt has been spending almost all of his time with son Jack after announcing his separation from his son’s mother and wife of eight years, Anna Faris.

And on Friday evening, Pratt, 38, shared his first Instagram photo since publicly revealing the news of his split on Aug. 6.

In a picture featuring the 5-year-old and his brother Cully, the actor gave a bicep pose to the camera following a viewing of the new movie Thor: Ragnarok, starring fellow Marvel member Chris Hemsworth.

Little Jack can be seen adorably flexing his muscles in the middle wearing an orange shirt and his dark-rimmed circular glasses.

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RELATED GALLERY: Everything Anna Faris Has Said About Husband Chris Pratt Since Their Split

“HOLY CRAP!! THOR RAGNAROK IS ABSOLUTELY AMAZING!!! We just laughed our asses off!!! So proud to be part of the Marvel universe,” Pratt captioned the photo of the trio.

In a joint statement regarding their separation, Pratt and Faris, 40, said, “Our son has two parents who love him very much and for his sake we want to keep this situation as private as possible moving forward.”

While Pratt has remained relatively silent about their estranged relationship, Faris has been open about the split.

“We’ll always have each other and be incredible friends,” the Mom star told PEOPLErecently.

“It’s understandable that people seemed so invested in our happiness together. All I can say about that is, it’s all true, that we truly adore each other, and we love each other, I think it still comes through,” said Faris, who’s romantically linked to cinematographer Michael Barrett.

Recently, Pratt wrote that the former couple will be “just fine” and plan to move forward by continuing to “amicably co-parent a human” together in the foreword of Faris’ book, Unqualified.