Early risers and planet gazers were treated to a cosmic event when Venus and Jupiter appeared side by side in the sky.

Jupiter, the solar system's biggest planet, and Venus could be seen with the naked eye on the east-southeast horizon shortly before sunrise on Monday.

Despite being hundreds of millions of miles apart, the two planets appeared barely inches away from each other in the sky.

Images of Venus on the left and Jupiter on the right were shared on social media.

The planets seen from Brighton. Credit: PA

Venus and Jupiter last appeared together in 2015 and 2016.

The two planets are expected to be visible again on Tuesday morning, but they will not be as close.

According to Nasa, stargazers will also be treated to another pairing later this month, when Saturn will meet Mercury on the western horizon at dusk on the 24th and 28th.

Brendan Owens, of the Royal Observatory Greenwich, said conjunctions are not uncommon, but Monday morning's display was a rarer occurrence because the planets appeared so close to each other.

He said the two planets were separated by "just over half the apparent size of the full moon in the sky".

"These events show us celestial mechanics in action as we are orbiting the Sun along with the other planets on a roughly flat plane," Mr Owens said.

"The planets closer to the Sun take a shorter time to orbit than those further out, leading to plenty of opportunities to see a conjunction."