Jennifer Garner confronted Lindsay Shookus, Ben Affleck's new girlfriend, after learning of their affair, sources tell People.
The actress, 45, allegedly approached the Saturday Night Live producer about the relationship while on a work trip in New York in 2015 -- when both of them were still married.
“Lindsay refused to back down or quit the affair,” the insider said.
The publication goes on to quote a source close to Lindsay who claims “Jennifer and Lindsay do not have any relationship.”
What’s more, sources also say the actress, perhaps best known for her performance in the spy-action thriller Alias, sought out Lindsay’s ex-husband, Kevin Miller, to speak about the affair.
The insider explained that she showed him text messages between the pair, adding: “She had proof.”
Ben, 44, and Lindsay, 37, were recently spotted enjoying a romantic dinner for two in Los Angeles, and fresh reports claim they’re already living together.
“They are spending time together in L.A. Lindsay is staying at Ben’s new house,” a source confirms to People.
Insiders claim the pair have actually been hooking up with each other on-off for several years.
“Ben and Lindsay started their affair about three years ago,” an insider alleged to US Weekly.
“They were not casually dating — they were having a full-blown affair," one source claims.
WATCH: Jennifer Garner gets real about her relationship with Ben Affleck. Post continues...
However, a source close to Ben – who was famously accused of cheating on Jen with their kids’ nanny, Christine Ouzounian - denies the affair, revealing that he and Lindsay have only been dating for three months.
"Lindsay was not what led to the end of their marriage. They had a ton of other problems,” said the source.
"Ben is enjoying Lindsay’s company, and they will continue to see each other."
Ben’s new romance comes only months after Jen officially filed for divorce after splitting in June 2015.
The couple’s divorce has been dubbed as “friendly” and is being compared to that of Gwyneth Paltrow and Chris Martin, who “consciously uncoupled” without complication in 2014.
The former couple share three kids together -- Violet, 11, Seraphine, eight and Samuel, five.