Rihanna and Adele have been pretty vocal about their mutual girl crushes on one another for some time now. It should, therefore, come as no surprise that Ri didn't let the Brit singer's 24th birthday (May 5) go by without sending her a very special -- slightly naughty -- surprise, AOL Music reports!

According to The Sun, RiRi sent Adele a birthday cake in the shape of boobs! Typical Rihanna. The "Birthday Cake" singer's sweet treat was reportedly topped off with "pink icing, sponge and and two strategically placed iced gems." We'd love to see a photo of that!

The Twitter-loving star also sent a birthday shout out to the "Someone Like You" songstress on the social media site. May 5 was also her ex Chris Brown's birthday, too, whom she also sent a tweet to.

The blinged-out baked good was reportedly delivered to Adele's North London home for her birthday party and accompanied by a message that read, "To Adele Laurie Blue Adkins, the baddest b----h around. Have the best freaking Bday. Cake cake cake xxx."

See Photos of Rihanna at 2012 Met Gala