Jennifer Lopez and Alex Rodriguez. Picture: JLo/Instagram

Jennifer Lopez has gushed about boyfriend Alex Rodriguez in a sweet birthday post on social media, in which she admitted her heart "skips a beat" whenever she sees her beau.

The 48-year-old singer has taken to social media to celebrate her beau, who turned 42 on July 27, by sharing a heartfelt message about the former New York Yankees baseball player. 

Alongside a photograph of the sportsman looking dapper in a sleek tailored suit, which Jennifer shared on her personal Instagram account, wrote: "Happy Birthday to the man who makes my heart skip a beat every time he walks in the room... (sic)."

The 'The Shades of Blue' actress wished her lover the "best year ever" and has admitted she is "so excited" for her partner's future. 

Her post continued: "Wishing you the best year ever my love...so excited for everything God has in store for you... #thebestisyettocome#itsyourday #mimacho #amormio #happybirthday #LEO #13 (sic)."

The message comes shortly after Jennifer - who has nine-year-old twins Max and Emme with her former partner Marc Anthony - turned 48 three days prior to Alex's birthday on July 24. 

And to mark the couple's special days they shared a joint birthday party over the weekend, which was extended to Monday (24.07.17) for Jennifer, who enjoyed a more intimate bash in her garden. 

The star was given a three-tiered birthday cake, which was decorated with white and gold-coloured icing, edible gold-painted roses and two sparklers, from Alex and his two daughters Ella, nine, and Natasha, 12. 

Jennifer and Alex are no strangers to publicly showing their love for one another, as the vocalist previously praised her beau as a "beautiful person".

She said: "He's a beautiful person. 

"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."