Madonna's daughter Lourdes hits the beach in black bikini, flashes armpit hair: Photos

In case you've forgotten the power of a classic black bikini, Lourdes Leon is here to remind you. 

The 20-year-old daughter of Madonna hit the beach in Miami on the weekend, looking every bit cool in a triangle two-piece, her hair pulled half-up in a topknot and her au naturel arm pits on show. 

It's not the first time Lourdes has flaunted her armpit hair. Last year, she posted a picture to Instagram with the caption, "#rebelheart the reactions lol" with the unicorn, love heart and squirrel emoji.

It followed an Instagram post from her famous mum in 2014, that showed the popstar posing with her arm raised, with the caption, "Long hair...... Don't Care!!!!!!"

Despite it not yet being Summer in the States, it didn't stop Lourdes from taking a dip in the Atlantic Ocean.

Lourdes splits her time between New York -- where she lives with Madonna, 58 -- and the University of Michigan, where she is enrolled in musical theatre. 

Lourdes' father, personal trainer Carlos Leon, also lives in New York with his wife, Danish designer Bettina Holt. Her siblings include Rocco, 16, David Banda, 11, Mercy James, 10 and four-year-old twins, Esther and Stella.