Katie Holmes shines in a rainbow cardigan celebrating her 40th birthday with Jamie Foxx and mom

Katie Holmes just turned 40 and she still loves the rainbow as much as any kid.

On December 18, the actress celebrated her birthday with a dinner outing to Serendipity 3, a restaurant in New York City.

She was joined by her mother Kathleen Stothers-Holmes and boyfriend Jamie Foxx. Her 12-year-old daughter Suri was not present for the occasion.

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A Us Magazine source described the couple:

"Katie and Jaimie looked happy. They both came in the same car together, with her mom. Her mom walked out with a cake box at the end."

She even found out what the group ate:

"Jamie and Kathleen ordered their frozen hot chocolate, and Katie had a strawberry sundae. [They] all seemed like they were having a great time."

Not only did she look happy, but Holmes also reflected the Christmas spirit. She wore a floor-length multi-colored cardigan. Underneath, she had on a gray top and a pair of mom jeans.

The actress was on the quiet side for her birthday. On her Instagram, she posted a simple photo of herself kneeling in front of angel wings and looking up. She captioned it with some smiley faces.

The A-lister tends to remain discrete when it comes to sharing her private life in the world. For the most part, her Instagram is useful in finding amazing recommendations of various things.

Take the movie "Ben is Back," which Holmes called "incredible." She described stars Julie Roberts and Lucas Hedges as being "phenomenal" in the film.

Holmes has also posted a picture of a few books she's read. They include "Essential Essays" by Adrienne Rich, "Educated" by Tara Westover, and the classic "To Kill a Mockingbird" by Aaron Sorkin.

While Holmes and Foxx were not seen showing affection last night, the pair finally let loose back in August.

The two were photographed in Malibu playing volleyball, wrestling in the sand, and even sharing passionate kisses. It was a rare sighting of the pair who have never officially confirmed a relationship.

They were first spotted looking romantic back in 2015. Prior to that, Holmes was married to fellow actor Tom Cruise whom she shares her daughter with.