Playboy model Hannah Ferguson wears the world's smallest bikini and fans are wearing it.

During her birthday celebrations, Playboy model Cassandra Sienega wore a bikini that one fan called the world's tiniest.

The barely there swimwear that covered her private parts in the picture has now racked up 40,000 likes on the photo-sharing app.

She celebrated her 34th birthday at the pool.The best birthday ever!I will definitely be back.

Three small pieces of pink fabric were strung together and held in place by transparent strings.

Many commenters were complimentary of the model's figures, but others made fun of them.