Ariana Grande Celebrates Her 25th Birthday With Fiancé Pete Davidson by Her Side. Posted by Blaze Alvarez Date: June 26, 2018 No need to add any sweetener to this soirée—it looks like Ariana Grande‘s 25th birthday celebration was her sweetest yet. https://www.eonline.com/news/947126/ariana-grande-celebrates-her-25th-birthday-with-fiance-pete-davidson-by-her-side