A GROUNDBREAKING announcement that could hint at the existence of alien lifeforms in our solar system and beyond is coming this week.

Nasa will reveal its discovery in a news conference on "Oceans Beyond Earth" this Thursday.

2 Nasa scientists have discovered something very, very exciting using the Cassini space probe and Hubble telescope

Scientists have made the discovery using the Cassini space probe, which has been monitoring mysterious Saturn and its moons, as well as the Hubble telescope.

Titan, a moon of Saturn, is believed to have an ocean hidden beneath its frozen crust.

Stargazers also believe Europa, one of Jupiter's moons, has a similar feature.

Could these secret seas be home to alien lifeforms?

The US space agency today announced: "Nasa will discuss new results about ocean worlds in our solar system from the agency’s Cassini spacecraft and the Hubble Space Telescope during a news briefing 2 p.m. EDT [7pm BST] on Thursday, April 13.

2 An artist's impression of Cassini swooping by Saturn's rings

"These new discoveries will help inform future ocean world exploration - including NASA’s upcoming Europa Clipper mission planned for launch in the 2020s - and the broader search for life beyond Earth."

It follows the announcement that Nasa’s Cassini spacecraft will be killed off in a spectacular suicidal nosedive after orbiting Saturn for 12 years.

The spaceship will end its mission with 22 daring loops passing through the mysterious gap between Saturn and its rings.

Since arriving at Saturn in July 2004, spacecraft Cassini has been exploring the giant planet and its 62 known moons.

This includes Titan, thought to resemble an early Earth, and the ocean-bearing moon Enceladus, which is mysteriously shooting ice particles out into space.

It was responsible for beaming incredible pictures back of the Death Star-style moon Mimas, and a “UFO” moon which looks bizarrely like Donald Trump.

Nasa's Cassini spacecraft: The best bits By 2017, Cassini will have spent 13 years in orbit around Saturn, following a seven-year journey from Earth. It has expanded our understanding of the kinds of worlds where life might exist. It's shown us Saturn’s largest moon, Titan, Cassini, which is one of the most Earth-like worlds we’ve ever encountered, with weather, climate and geology that provide new ways to understand our home planet. Cassini is, in a sense, a time machine, Nasa explained. It has given us a portal to see the physical processes that likely shaped the development of our solar system, as well as planetary systems around other stars. The length of Cassini’s mission has enabled us to observe weather and seasonal changes, improving our understanding of similar processes at Earth, and potentially those at planets around other stars. We now know more about its moons, including their bizarre shapes. There's Iapetus' with its noticeable ridge around its equator and a two-toned color pattern and Mimas which looks like the Death Star from Star Wars. Hyperion looks like a sponge and another, called Atlas, more like a flying saucer. Cassini showed us that Prometheus is shaped like a spud and Pan resembles Italian ravioli.

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