If you've ever peered into the night sky and wished upon a star you've probably got a pretty firm idea of what a star looks like, but new research has found you'd probably be wrong.

The international research led by an Auckland astronomer has found stars are not just round twinkling dots in the distance - they can also be oval or cigar shaped.

Dr Ian Bond from Massey University says researchers have suspected for some time that stars come in various shapes and sizes, but there wasn't any observational data to confirm their suspicions as the stars are so far away.

The star that blazed the trail for the astronomers was observed at the Mt John observatory in Tekapo.

"To just compare the distances, our sun is eight light minutes away and this star that we observed was 15,000 light years away," says Bond.

The technique scientists used is gravitational microlensing, which is the same technique used by New Zealand astronomers who recently discovered a massive planet.

It is the first time the technique has been used to determine the shape of the star.

Gravitational microlensing, which was first described by Einstein in 1936, enables a distant star to be effectively magnified by the gravitational field of a nearer collinear star.

Our sun as it turns out is slightly more cigar shaped than expected - shedding light on a symbol that may now need a makeover.