He’s stepping up to the plate with a new lady.

The “mystery woman” spotted locking lips with former Yankees slugger Alex Rodriguez at Michael Rubin’s star-studded Fanatics bash in the Hamptons last week is private fitness coach Meghan Hayden, multiple sources tell Page Six.

One source tells us, “They are dating. It’s new. She’s a really nice person from a great family.”

The new couple was spotted looking cozy once again at Bounce Beach in Montauk over the holiday weekend.

“They came with a crew of people and definitely looked coupled up,” a spy tells us. “There were other girls trying to talk and flirt with him, but the friends at the table nicely redirected them.”

We’re told the group danced the night away at the hotspot to sets by model and DJ Ethan and Little Fax the Machine.

A-Rod and Hayden were also seen sitting on a bench in Sag Harbor.

Hayden is a private fitness coach, former Division I athlete and University of Miami graduate, where she earned a bachelor’s degree in exercise physiology, according to her website, “Take Off With Meg.”

“When Meghan isn’t training clients, she’s most likely biking to her next session or modeling on set with household brands like Under Armour & Athleta,” her bio reads.

Rodriguez’s budding romance comes after his split from longtime girlfriend Jaclyn Cordeiro. The pair dated for three years before quietly calling it quits around March, a source previously told Page Six.

Coderio told TMZ in May, “Alex and I are currently taking some time apart but there continues to be mutual love, care, and deep respect between us and for our families.We remain supportive of one another, and there is absolutely no animosity, drama, or negative story here,” she added.

Cordeiro shared that she is also “navigating a serious health matter involving a family member at this time.” 

Since the announcement A-Rod was spotted flirting with multiple women at celeb-packed hot spot the Corner Store in New York City.

Last Wednesday, he was photographed kissing Hayden at Rubin’s celeb-packed party in Bridgehampton.