Jennifer Lopez and Alex Rodriguez enjoyed a joint birthday celebration in Miami over the weekend

The chart-topping star and Alex - who turns 42 on Thursday (27.07.17)

- couldn't keep their eyes off each other, according to the New York Post newspaper, which also revealed the celebrity duo playfully sang 'Sweet Caroline' as part of the celebrations.

Jennifer and Alex have been dating since February this year - and an insider recently claimed the duo are "incredibly happy" together.

Their relationship is reportedly going from strength to strength because Jennifer is able to "start talking sports" with any of Alex's high profile pals.

The source explained: "They are incredibly happy. Jennifer is on another level for Alex when compared to his past girlfriends. She's amazing.

"She comes to this dinner and there are 20 people there, a lot of sports celebs and big guys in the business, and she can sit right down with them and start talking sports. She loves baseball."

And Jennifer is similarly complimentary about her beau, describing Alex as a "beautiful person".

She previously said: "He's a beautiful person ... I think people are gonna really ... in the next year or two really get to see who this person really is, you know? He played baseball, he was so focused for so many years, he's one of the greatest of our time, but as a person, I think, you're gonna see who he really is.

"He's a loving father. He's a generous human being with his family, with his friends, with me. He's caring and sweet and capable and responsible and just all the beautiful things you would want a man to be.

"I feel really lucky right now, so I'm excited about life, but I'm more excited for people to get to see who he really is."