The improved design includes features such as offline support, smart replies and a snooze option to deal with annoying messages.
Google is hoping the update will give a 'fresh, clean look for Gmail on the web' - although it has revealed very few details.
The Verge, however, has obtained a series screenshots that show three new layouts.
The new design features a sidebar with the option of using the Calendar, Keep note-taking app and tasks next to user's emails.
This could make it easier to schedule meetings and check availability while emailing people.
A default view highlights attachments such as documents and photos, a comfortable view doesn't show attachments, and a compact view shows more messages.
G Suite administrators, who manage the online Google domain, gave some details of the design to 9to5Google.
They said Google apps will be better integrated with 'easy access' to services like Calendar from within Gmail.
The 'snooze' button will also temporarily hide emails from user's inbox until a certain time.
Both Snooze and Smart Reply are part of Google's Inbox app on Gmail.
Google is also reportedly moving the existing stand-alone app, Gmail Offline, to a web-based variant.
'We previously announced that we're moving Chrome apps, like Gmail Offline, to the web. As part of this effort, we'll introduce native offline support in the new Gmail experience by June 2018,' Google said.
'We'll provide more details about this new offline setting and the eventual shutdown of the Gmail Offline Chrome app in future communications on the G Suite Updates blog.'
The update will be first be available as an early access program for G Suite customers and people with personal accounts.
Sources say that popular Chrome extensions should continue to work in the new Gmail.
'We're working on some major updates to Gmail (they're still in draft phase)', a Google spokesperson told MailOnline.
'We need a bit more time to compose ourselves, so can't share anything yet—archive this for now, and we'll let you know when it's time to hit send.'
Recently the company release a new design for Google Calendar with modern icons and colours.
The design - which looked more like the mobile app - could give a clue as to how the latest update will look, writes the Verge.
The design looked more like the mobile app meaning Gmail itself could be updated in a similar way.
The Daily Mail
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