Shakira posted this picture yesterday, with the caption: 'Official single art for "CAN'T REMEMBER TO FORGET YOU" with @Shakira #4daycountdown'

London - Shakira thinks Rihanna is the "sexiest woman on the planet".

The Colombian singer has teamed up with the Bajan beauty on a new track, 'Can't Remember to Forget You' - which will be released on January 13 - and the pair hit it off instantly, with the 'Diamonds' hitmaker even teaching her new pal to dance.

Shakira said: "Working with her was utopia. She's the sexiest woman on the planet. And at the end of the day, we're both just basically Caribbean girls. The chemistry was so good and so real. She taught me dance moves. She was a sweet teacher."

The 36-year-old beauty - who has 11-month-old son Milan with partner Gerard Pique - insisted she doesn't feel "pressure" to maintain a slim figure because the soccer star prefers her to be curvier, and she has more important things to think about than dieting.

Speaking to the February edition of America's Glamour magazine, she said: "My man, Gerard, prefers meat over bone. He doesn't like too skinny. [Laughs.] That takes pressure off. I already have a lot to worry about. This month I'm not exercising because I have an album to finish and I have a baby. And I like these pastries in front of me."

Shakira - who is set to return to the coaching panel of 'The Voice' USA alongside Usher, Adam Levine and Blake Shelton next month - finds it can be "challenging" working alongside so many men, including in her recording career, but she says having a "tough hide" helps her in such a male-dominated industry

She said: "Dealing with boys at work and being the only girl can be challenging. I have my insecurities, but I've learned I have to be a good sport. I have to be able to take certain jokes and not take them personally. There are jokes made almost every second of the day. I had to develop a tough hide.

"You know, the music industry is dominated by guys. I work with men 98 percent of the time - producers, arrangers, musicians, engineers." - Bang Showbiz