THINK you know your star sign? Think again, because NASA has added a new sign to the Zodiac.

The new star sign, Ophiuchus, has been added because the organisation has re-assessed the ancient star calendar.

A NASA spokesman said the ancient Babylonians divided the zodiac into 12 equal parts, choosing one constellation for each.

But there were actually 13 constellations in the zodiac, so they chose one - Ophiuchus - to leave out.

These are the signs now:

Capricorn: January 20 to February 15

Aquarius: February 16 to March 11

Pisces: March 11 to April 18

Aries: April 18 to May 13

Taurus: May 13 to June 21

Gemini: June 21 to July 20

Cancer: July 20 to August 10

Leo: August 10 to September 16

Virgo: September 16 to October 30

Libra: October 30 to November 23

Scorpio November 23 to November 29

Ophiuchus: November 29 to December 17

Sagittarius: December 17 to January 20