Robert De Niro, 80, walks hand-in-hand with girlfriend Tiffany Chen, 45, at star-studded White House state dinner for Japanese PM Fumio Kishida - days after celebrating daughter Gia's first birthday

Robert De Niro and girlfriend Tiffany Chen were among the A-list stars to attend President Joe Biden and First Lady Jill Biden's state dinner for Japanese prime minister Fumio Kishida at in Washington, D.C. on Wednesday.

The Oscar-winner, 80, and Chen, 45, were photographed walking hand-in-hand through the White House along with Amazon billionaire Jeff Bezos and former President Bill Clinton. 

Robert, a typically low-key star, suited up for the occasion in a black tuxedo with a white dress shirt, black tie and black patent leather dress shoes.

Chen looked elegant in a white strapless gown styled with an off-white shall, black high-heels and a clutch purse.

While heading through the entryway with Chen, Robert was asked how he felt about the 2024 election, to which he replied: 'What do you think?'

He ignored a question about whether he'd campaign for Biden.  

Japanese Prime Minister Fumio Kishida and his wife Yuko were greeted by President Biden and First Lady Jill Biden upon their arrival at Wednesday's dinner.

The Bidens transformed the White House into a spring garden - complete with a koi pond and floating lily pads - for the event. 

The inspiration for the evening was spring in both nations, White House Social Secretary Carlos Elizondo noted. Event designer Bryan Rafanelli, who also planned Naomi Biden's White House wedding, came in to help with decor.

Legendary singer Paul Simon will perform for guests after their meal of home cured salmon, rib eye steak and salted caramel pistachio cake with cherry ice cream.

Kishida is the fifth state guest of Biden, who has also hosted leaders of India, Australia, South Korea and France.

Biden is hosting Kishida for the first state visit by a Japanese leader in nine years.

A state dinner is the highest honor the United States can give an ally.

Just four days ago, Robert and Chen — who were first romantically linked in 2021 — celebrated their daughter Gia Virginia Chen De Niro's first birthday on April 6. 

The happy couple confirmed the news of their child's arrival a month after her birth. 

De Niro began dating Chen in August 2021, following his split from ex-wife Grace Hightower in November 2018.

In addition to Gia, De Niro is also a father to six other children, which includes Drena De Niro, 56, and Raphael De Niro, 47, whom he shares with ex-wife Diahnne Abbott.

He also has twin sons Julian De Niro and Aaron De Niro, 28, from his longtime romance with former girlfriend Toukie Smith and Elliot De Niro, 25, and Helen Grace De Niro, 12, whom he shares with Hightower.

Robert gushed over Gia in an interview with PEOPLE in February. 

'She's such an adorable baby. So sweet,' the Raging Bull star told the outlet. 

'[When I] look at her, everything else goes away. So it's a great joy and relief to just be with her in the moment.' 

Robert sees 'a lot of similarity' between himself and baby Gia.

He said that Gia's siblings 'get a big kick out of' her and that she also gets lots of love from his brother Raphael's three young children.

'She's their aunt— [and] they're about to be teenagers!' he remarked.

Robert said that seeing all his children together 'is everything to me' and that he cherishes 'just being together, taking trips to warm places.'