The marriage will take place in Hawaii.
The second term Democratic Congresswoman from Hawaii, Gabbard, 33, had announced her engagement about a month ago.
She disclosed the identity of her fiancee in an interview to the local Honolulu Star Advertiser published this week.
"Both Abraham and I are generally kind of private people. He has nothing to do with politics. He's a humble, great guy who doesn't want to be in the limelight, so this is something new to the both of us," Gabbard told the daily newspaper in an interview.
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This would be Gabbard's second marriage and the first one for Williams.
Gabbard said she would keep her last name after the marriage, which she wants to keep it a low key affair.
Invitation for the wedding are expected to go out this week. Which among others include US President Barack Obama.
Williams is a freelance cinematographer who has made some short films and worked on commercial and political advertising campaigns, the daily reported.
While Gabbard's first marriage took place before a justice of the peace with only a few family members in attendance, the daily said this time she is planning a Vedic wedding ceremony in keeping with the couple's Hindu faith.