The Proposal actor, 34, was snapped getting close to German model Agnes Fischer in Cape Town, South Africa, earlier this week.
In a photo taken near the set of Ryan's upcoming movie Safe House, which co-stars Oscar winner Denzel Washington, Ryan was seen walking side-by-side with the 25-year-old blonde.
Agnes, who is something of a ringer for Hollywood actress Michelle Williams, showed off her tanned and toned body in cut-off shorts, trainers and a plaid shirt.
She has modelled underwear as well as skimpy sports clothes for top brands including Adidas.
Ryan was just as casually dressed in jeans, a green sweatshirt and carrying a backpack.
The actor's estranged wife Johansson is believed to be dating two-time Oscar winner Sean Penn.
The 26-year-old Iron Man 2 actress and Sean, 50, were spotted having lunch together on Tuesday at Cuban restaurant Versailles in Los Angeles.
As the pair ate, Scarlett placed one of her feet on Sean's lap - a move which suggests the pair may be better acquainted than they have let on.
Dressed casually in jeans and a striped T-shirt, Scarlett looked relaxed and happy as she and Sean laughed and chatted throughout the meal.
The couple were rumoured to be dating last month just weeks after Scarlett announced her divorce from Ryan Reynolds
The pair were first linked back in January, just weeks after Scarlett announced her divorce from her husband of two years, actor Ryan Reynolds.
The are said to have met at the Chateau Marmont in West Hollywood while Scarlett was filming We Bought A Zoo, her new movie alongside Matt Damon.
Earlier this year, Ryan was linked to his Proposal co-star Sandra Bullock, after the two spent New Year's eve together at Sandra’s restaurant in Austin, Texas.
But both denied any type of romantic relationship, with Sandra telling Al Roker of the Today Show: 'I think there will be a collective sigh amongst women across the United States when I say he’s not my lovah, she joked. 'He’s just an amazing friend for 10 years … but I don’t get his loving after dark.'