Kate Beckinsale and New Boyfriend Matt Rife Are 'Totally Smitten With Each Other,' Source Says

The new celeb couple is really hitting it off!

Kate Beckinsale and Matt Rife are really hitting it off.

The 43-year-old actress and her 21-year-old comedian new beau were spotted out together at the Sherman Oaks Galleria in Sherman Oaks, California, on Sunday night, where they weren't shy about showing plenty of PDA, and took adorable photos together before catching a movie. As for what the two saw, an eyewitness tells ET that the only picture showing at the time they arrived was Transformers.

Following the movie, Rife drove Beckinsale back home.

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"Kate was really happy. She looked completely smitten with Matt," the eyewitness reveals. "Kate was always touching him the entire time they were waiting for the car at the valet. They were also holding each other as they rode on the escalator. Kate was kissing him. They were super affectionate."

Sounds like it was a really good night!

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A source close to the couple tells ET, "Kate and Matt are totally smitten with each other. They’re happy that the news is out that they are together and they don’t have to sneak around anymore."

"Kate and Matt are having fun. The age difference isn’t really an issue," the source adds. "Matt is very mature for his age and wise beyond his years ... [he] has dated girls in the past but this seems the most serious."

WATCH: Kate Beckinsale and Daughter Lily Show Off Their Toned Bods in Bikini Pics

Meanwhile, the actress is officially ready for swimsuit season, judging by her recent bikini pics!

Watch the video below for more.

Reporting by Jennifer Peros and Kayley Stumpe.

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