But the father is somewhat of a mystery to many.
Unlike 45-year-old Sevigny, Mackovic, 33, is not a Hollywood actor. Instead, he is part of the art world and serves as the director of Karma Art Gallery in New York City. He has held that position since 2011, according to his LinkedIn.
His gallery was involved in last year’s starry Miami Art Basel Fair, including pieces by Alex De Corte, Henni Alftan and Woody De Othello, with prices ranging from $10,000-$200,000, according to The Art Newspaper.
While the gallerist clearly mixes with high-profile people, he still values his privacy.
Both his LinkedIn and Instagram profiles are void of any current photos of himself.
Mackovic, who is Serbian, has been dating “The Act” star for more than a year.
They are expecting their baby in the spring.