They were pictured in Dublin yesterday when he touched down with his daughters James (4) and Inez (2) to visit his wife.
It looks like the girls were enjoying Irish living as they were pictured holding some traditional fare, a pack of Tayto crisps.
Going for a casual look, the actor wore a navy cap with a white shirt and jeans as he made his way through the city.
The Gossip Girl actress (30) was in the capital last year filming for the thriller, but production was halted after she sustained a hand injury on set.
The film, due for release next February, follows Lively in the lead role of Stephanie Patrick, a woman who seeks revenge against those who orchestrated a plane crash that killed her family.
The movie, some of which will also be shot in Spain, also stars Jude Law and Black Panther actor Stephen K Brown.
The Rhythm Section is being produced by Michael G Wilson and Barbara Broccoli of EON Productions, who produced the last eight James Bond movies, while The Handmaid's Tale's Reed Morano is also involved.
Lively was spotted around the north inner city last year while she was filming the thriller. The actress looked almost unrecognisable in a brown coat and blue hat.
Other images have emerged of her donning a short brown wig, suggesting her character may go under disguise in the flick.
The couple enjoyed some down time in between Lively's work last year.
Reynolds was spotted taking a stroll around Dublin's Fitzwilliam Place and he paid a visit to the Powerscourt Estate in Co Wicklow.
They were also spotted enjoying a coffee at Bear in Blackrock. The pair were said to be renting a large home in Killiney for their stay.
Reynolds and Lively first met in 2010 when they starred together in the Green Lantern. It was reported the following year they were dating.
They married in September 2012 in South Carolina with their first daughter James born in 2014.
The actors are the latest famous faces to be spotted around Ireland.
Alanis Morissette enjoyed a trip to Dublin in recent weeks after she performed at Live At The Marquee in Cork. Accompanied by her family, she was seen strolling around the grounds of Trinity College. Katie Holmes was also in Ireland for the heatwave.