The 'Dang!' hitmaker has paid tribute to his girlfriend as she reached the milestone birthday, calling her an ''adorable pure soul''.
He wrote on Instagram: ''Happy Birthday to this adorable pure soul who has reminded me what being happy feels like. Thank you for loving me so good. I think it's supposed to be ''so well'' but I don't care. I love you and can't wait for all of the adventures. (sic)''
Ariana's mother Joan also took to social media to send her birthday wishes to her daughter.
She shared: ''Happy Birthday to my fabulous daughter @ArianaGrande ...so so so proud to be your mama!! I love you!! #HappyBirthdayAriana (sic)''
Whilst Ellen Degeneres wrote: ''Happy birthday, @ArianaGrande. You light up the world. (sic)''
And Ariana's fans flooded Twitter with messages of love and support for the 'Dangerous Woman' hitmaker.
One wrote: ''happy birthday cuttie pie i love u thanks for inspiring me every day to be a better person (sic)''
Whilst another added: ''HAPPY BIRTHDAY @ArianaGrande, you are my moonlight, my angel, and my sunshine. I love you more than you'll ever know (sic)''
And a third shared: ''happy birthday to the most amazing girl in the world @arianagrande i can't believe she is 24! I love u so much, hope u have the best day. (sic)''
Ariana is set to get a late birthday present next month when she will be named an honorary Mancunian. The honour will be bestowed on her after she staged a benefit concert in the city to raise funds for those affected by the Manchester terror attack, which happened after her concert on May 22 and left 22 people dead and more than 50 injured.
Town hall boss Sir Richard Leese said recently: ''We've all had cause to be incredibly proud of Manchester and the resilient and compassionate way in which the city responded to the terrible events of May 22 with love and courage, rather than hatred and fear. Ariana exemplified this response. I think many people would already consider her an honorary Mancunian, and we would be delighted to make it official.''