Jennifer Lopez in birthday dance-off

Jennifer Lopez showed off her moves in a "hot" salsa dance-off at her surprise birthday party this week.

The stunning songstress turned 43 on Tuesday and was astonished when boyfriend Casper Smart organised a bash for her aboard luxury yacht Utopia III.

Jennifer enjoyed herself with friends including Mary J. Blige and manager Benny Medina and was seen flaunting her dance moves during the celebrations.

"J.Lo got behind the bar and poured shots of Patron for other guests. She then embarked on an intense and hot salsa dance-off with her friends and dancers on the floor," the New York Post writes.

Jennifer was blown away by 25-year-old Casper's efforts; she also received a diamond necklace with a pink teddy bear - a nod to the term of endearment they reportedly use for each other. The singer was blindfolded ahead of the big reveal.

"[She] took it off when the guests yelled 'Happy Birthday' over the side of the yacht," the source added.

Once on board the luxury vessel, Jennifer blew out the candles on her cake which was in "the shape of an oversized teddy bear".

Celebrations lasted well into the night, with the party reportedly finishing around 4am.

Meanwhile, the promo for Jennifer's new single Goin' In debuted on MTV First: Jennifer Lopez on Wednesday.

The colourful video - which features Flo Rida - shows Jennifer in an array of costumes, including a dramatic hot pink cape. The star dances with a team of dancers throughout the four-minute clip.