The timing of this conjunction, as the celestial event is known, has caused some to suggest it may have been the source of a bright light in the sky 2,000 years ago.
That became known as the Star of Bethlehem.
The planets are moving closer together each night and will reach their closest point on 21 December.
Keen stargazers in the UK will have to keep a close eye on the weather to avoid an astronomical disappointment.
