Scarlett Johansson is getting hitched!

At a dinner thrown by Martha Stewart at her East Hampton estate, the 29-year-old actress revealed that she and her French fiancé Romain Dauriac with whom she is expecting her first child, will tie the knot in four weeks, the New York Post newspaper reported.

The Avengers star got engaged to French journalist Dauriac in September last year.

The wedding venue is kept secret, but it is expected that the actress will either get married in her fiance's native Paris, or in the Hamptons, where they have spend most of the summer together.

Scarlett and Romain were joined at the dinner, which marked the launch of $400-a-bottle Dom Pérignon's P2-1998 champagne, by the likes of Howard Stern and his wife Beth Ostrosky, Katie Couric, Matt Lauer, Barbara Walters, Rachel Zoe and Harvey Weinstein.

The star has admitted she would probably "wing it" on her big day.

She said previously, "I don't plan anything. I'm terrible at planning. Yeah, I'm not gonna plan anything - I like to wing it!"

Scarlett, who was married to Ryan Reynolds from 2008 to 2011, previously admitted she finds it "easier" to date someone, who is not famous.

She said: "It is easier to be with someone who isn't famous, but it's more than that. We do different things. He's Romain in the whole art-scene world. So it's nice, because we can enjoy each other's worlds, but we don't have our crazy conflicting schedules and all that other stuff to contend with."

Johansson's much-anticipated Luc Besson sci-fi movie Lucy releases this Friday.