Chris Stewart texted his ex-teammate and fellow Southern California native Gerrit Cole when news broke that the right-hander had agreed to a record-breaking, $324 million deal to join the Yankees.

“I told him, ‘Welcome to the Pinstripes and to go visit my monument in Monument Park,’ ’’ the retired catcher joked by phone Friday.

Stewart, who played two seasons in The Bronx in 2012-13 and then spent four years with Cole in Pittsburgh, has been talking to the pitcher about the Yankees since the two became teammates in 2014.

“He always had that connection with the Yankees, from growing up a fan to being drafted by them,’’ Stewart said. “He wanted to know what the fans were like, what the Stadium was like to play in and how it was to play in the city. It all led to this.”

Cole is about to find out for himself.

“I don’t think he’ll change anything,’’ said Stewart, who has compared Cole’s mentality to CC Sabathia’s. “He’s very confident in what he does. Off the field, he’s laid-back, but when he steps on the mound, he’s a beast. It doesn’t matter where he is, what the fans do or what stadium he’s in. I don’t foresee any obstacles for him in New York.’’

Stewart should know. He has caught more innings from Cole than anyone else in the majors (306¹/₃ innings over 48 starts) and they remain close.

“I think he was always curious about what it would have been like if he’d gone to the Yankees when they drafted him,’’ Stewart said of Cole’s decision to attend UCLA after the Yankees selected him with the 28th overall pick in the 2008 draft out of Orange (Calif.) Lutheran High School.

Stewart watched Cole bounce back from a career-worst year in 2017 with two stellar seasons in Houston, when he established himself as arguably the best pitcher in the game.

Stewart said he believes the turnaround was due to a combination of factors.

“I think the league started to figure him out after he’d been in the same division for so long,’’ Stewart said. “I’m sure he went into that offseason trying to figure out what went wrong and then going to Houston, where they’re really good at diving into things, he was able to get back to being so effective. The rest is history.’’

History that culminated in the nine-year deal Cole agreed to during the winter meetings.

Stewart called Cole a “sponge” due to his desire to pick up as much knowledge as possible from catchers, pitchers and hitters.

The main challenge in catching Cole, according to Stewart, was keeping him from getting too emotional.

“Sometimes you had to get him to tone down his drive,’’ Stewart said. “He could let one pitch get to him and have a negative effect on his mind. But I’d rather have a guy I had to calm down than kick in the butt. And he seems to have gotten better at controlling those things, seeing him pitch in the World Series.’’

Stewart is looking forward to seeing what comes next.

“He always had the stuff, but his mental game is what’s allowed him to go to take the next step,’’ Stewart said. “I don’t think there’s anyone you’d rather give the ball to right now and that’s the way he wants it.’’