"Jen introduced John to Ben because he'll obviously be around their kids, so it was the right thing to do," a source told Radar. "No one was more surprised than her when Ben and John immediately clicked."
Affleck, 46, offered to be there for Miller if he "needs advice on dating in the spotlight."
"John has taken him up on that," the insider said. "They text each other from time to time and there's no edge or awkwardness between them at all."
Garner, who shares children Violet, 13, Seraphina, 10, and Samuel, 6, with Affleck, "doesn't know whether to be weirded-out or happy about it!"
Garner, 46, has been dating the CaliGroup CEO, 40, for almost a year.
Their bromance is beneficial for Garner, as she continues to be involved in her ex-husband's life.
In August 2018, Garner was photographed driving Affleck, who has struggled with alcohol abuse, to rehab.
The exes were recently spotted on a church outing with their children in January.
Are you surprised Affleck and Miller are getting along well? Sound off in the comments.
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