According to People magazine, the stunning actress is engaged after accepting boyfriend Romain Dauriac's August proposal.
'I can confirm that Scarlett and Romain are engaged. They haven’t chosen a date for the wedding,' a rep for the 28-year-old told Harpers Bazaar UK.
Stunning: At a photo call for her new movie Under The Skin on Tuesday, the stunning star flashed her engagement ring from her French beau
Check out that bling! Scarlett's engagement ring features one large diamond as the centerpiece and then two slightly smaller ones on each side
Promoting her new film, Under The Skin, at the 70th Annual Venice International Film Festival on Tuesday, Scarlett had an undeniable glow.
The bubbly star was beaming from ear to ear as she took to the red carpet dressed in a figure-hugging, plunging black gown.
Earlier in the day she had attended a photo call wearing a Sonia Rykiel knitted top and black trousers.
And she proudly displayed the vintage Art Deco ring her French beau is said to have presented her with.
Scarlett's engagement ring features one large diamond as the centerpiece and then two slightly smaller ones on each side.
The three rocks are then surrounded by many other smaller stones.
It appears to be set in either a white gold or platinum setting and band.
Following news of the exciting development, the star and her new fiancé made a rather sheepish exit from the Italian city on Wednesday.
ScarJo made a concerted effort to hide her ring from photographers, twisting the sparkler around so only the platinum band was visible.
The Avengers star looked cosy as she left the sinking city dressed in black pants, a grey T-shirt, beige cardigan and dark grey scarf.
Camel-coloured heeled clogs and a navy blue New York Yankees baseball cap finished off the casual ensemble, while the actress donned large sunglasses and clutched a red blanket close to her chest.
Distraction mechanism: It was hard not to notice Scarlett's ring as she graced the red carpet that evening for the premiere of her new film, despite the fact that she was wearing a plunging black gown
Why so shy? The 28-year-old came across all coy the following morning, twisting her ring around and hiding her face
Something to hide? Scarlett went to great lengths to avoid her engagement bling being photographed on Wednesday as she left Venice, Italy
Romain was equally shy, attempting to cover his face with a book as he carried his luggage to their awaiting boat.
The journalist and creative agency manager looked smart in faded black jeans, a plain white tee, Converse sneakers and a light green jacket.
The couple began dating in November 2012 after being introduced by mutual friends, just weeks after the actress split from her boyfriend of one year Nate Taylor.
August proposal: The couple kept their heads down after news of their engagement surfaced, though a source insists they're 'engaged and very happy'
Rumours first began to swirl that the couple were planning to wed after the beauty was spotted wearing a huge pear-cut diamond ring as she wandered around New York with 30-year-old Romain in February.
Then in July, Scarlett was spotted wearing an ornate gold ruby ring - though friends dismissed reports she was engaged at the time, saying it was 'simply a piece of jewellery'.
The star admitted last year that she liked being married but hinted that she wasn't interested in tying the knot again for quite a while.
Quick getaway: The beautiful actress was barely recognisable as she made the trek to the airport following her stunning premiere appearance the night before
Change of tune: Scarlett previously stated that marriage is 'not important to me', though clearly Romain has opened her eyes to the possibilityShe said, 'I got married when I was young and it was incredibly romantic and I liked being married, actually.
'But it is different. It's hard to put into words. To me, being in a functioning relationship doesn't mean you have to be married.
'I never think about marriage. Is that weird? The only time I ever think about it is when people ask me. It's really not important to me.'
Johansson was married to Canadian actor Ryan Reynolds in 2008, before calling time on their union in 2010 and officially divorcing on July 1, 2011.
The Green Lantern star went on to marry Gossip Girl's Blake Lively on September 9, 2012.
Former flame: Scarlett was previously married to Ryan Reynolds, who is now married to Blake Lively (L)