Justin Theroux fueled engagement speculation with girlfriend Nicole Brydon Bloom, after she was spotted wearing a dazzling diamond ring on her left hand.

The 53-year-old ex-husband of Jennifer Aniston and the 30-year-old actress were pictured attending the 81st Venice International Film Festival in Venice, Italy on Wednesday.

The pair both matched in white for what was their second major red carpet appearance, as they promoted his new film Beetlejuice Beetlejuice at the event.

Justin and Nicole — who enjoyed a sporty outing in June — have been dating for over a year. They made their first official appearance at the Vanity Fair Oscar Party back in March.

DailyMail.com has reached out to Theroux's representatives for comment. 

The Leftovers star wore a custom cream Zegna suit jacket with a high-collar shirt. He accessorized with Tiffany & Co. jewelry and rocked a scruffy beard.

Meanwhile Nicole dazzled in a sleeveless white Akris dress that showed off her toned arms. 

The gown featured a high neck and a slit in the back. Her brunette tresses were slicked back in an elegant updo.

Justin and Nicole have only infrequently surfaced in public as a couple since they were first spotted together in February 2023.

The duo were seen walking down the street together in June, wearing sporty outfits.

Nicole and Justin reached a milestone last December when he accompanied her as her date to her twin sister Chrissy's wedding.

Nicole snapped a mirror selfie from the festivities that showed her and Justin beaming on a staircase amid a claque of loved ones including his dog Kuma.

They were also glimpsed kissing last August after a night out on the town. Just before the lip-lock, they had enjoyed an evening at Ray's, the New York dive bar that Justin owns with some friends including Succession actor Nicholas Braun. 

They were first romantically linked after hitting the picket line in NYC in support of the ongoing SAG-AFTRA strike. 

Nicole is best known for playing Caroline Stuyvesant in season two of The Gilded Age. 

She has also appeared in Law & Order: Special Victims Unit, 1BR, and We Were the Lucky Ones.

Justin also enjoys a famously amicable relationship with his ex-wife Jennifer, 55, whom he was with for a total of seven years. 

Justin and ex Jennifer were married from 2015 until 2017 but managed to stay friendly after what Justin has called a 'gentle separation.'

They announced their split in February 2018, and a few months later Justin told the New York Times how amicable the process had been.

'The good news is that was probably the most - I'm choosing my words really carefully - it was kind of the most gentle separation, in that there was no animosity.'

The Tropic Thunder writer added: 'In a weird way, just sort of navigating the inevitable perception of it is the exhausting part.'

He also spoke about the end of his relationship with Aniston during an interview with Esquire, where he affirmed that he was still close to his former spouse.

'Like it or not, we didn't have that dramatic split, and we love each other,' he said.

The Inland Empire cast member then stated that he wanted to remain in contact with the Friends star well into the future.

'I'm sincere when I say that I cherish our friendship. We can not be together and still bring each other joy,' he said.

Justin, who is three years younger than Jennifer, married her in Bel-Air in 2015 and they broke up about two years later.

Jennifer and Justin first started dating in 2011, having worked together on the film Wanderlust. 

He had carried on a 14-year relationship with costume designer Heidi Bivens that collapsed in 2011.

At the time, a friend of Heidi's told E! News claimed that Heidi had been 'straight-up dumped,' though the outlet made sure to qualify: 'Not to say it's Aniston's fault, maybe the timing was just terrible?'

A source in Justin's camp insisted to Page Six: 'Things were already over between him and Heidi before he got close to Jen.'

Heidi's mother Marilyn spoke to Radar Online in 2016, claiming that Justin initially tried to persuade Heidi he and Jennifer were not an item.

Marilyn asserted: 'Heidi told me what Justin had told her, that something was going to be written about him and Jennifer, that something was going on between them and he wanted her to know that it was nothing, there was nothing to it.'

In Marilyn's telling, Heidi allegedly ultimately discovered that the rumors were true, '[a]nd my sweet Heidi she calls me and says: "Oh mommy." I was going through cancer at the time. It was a time that hurt our family.'