Dave Grohl and co posted a picture of a microphone on a stand in the centre of a bath, seemingly suggesting they've recorded parts of it in a bathroom.
The 'All My Life' hitmakers captioned the snap posted on their social media accounts: "Come on in, the water’s fine…
#FF2020 #FF25 #happynewyear (sic)"
The unusual update comes after frontman Dave said their follow-up to 2017's 'Concrete and Gold' is "f***ing weird".
Asked how it'll differ, he replied: "You'll hear. It's f***ing weird."
Drummer Taylor Hawkins previously teased the group also have plans to celebrate their 25th anniversary this year.
Asked about their plans, the 47-year-old sticksman said: "Well, it's very possible.
"There's a lot of talk.
"And I think Dave is already mapping out what he wants the next record to be, so I wouldn't be surprised if there's something coming down the pipe.
"I can't 100 per cent spell it out for you for sure, because I'm always the last to know and I don't want to give it away.
"But I would imagine there will be something made of the 25th year of the Foo Fighters, for sure. You know us, we never stop."
Meanwhile, Dave recently admitted he doesn't think Foo Fighters have ever been "cool".
The 'Pretender' hitmaker insisted the band are "totally dad rock" but he likes their image and is content not to be seen as edgy.
When it was suggested the group were a cool band on podcast 'Good for You', the rocker told host Whitney Cummings: "You know the whole dad rock thing? We're totally dad rock.
"First of all, we are all dads, and you're right, we're a rock band... Look, I'm 50 years old, I have f***ing grey hair... But you know, the thing is, I have never considered our band cool, and I like that."
Dave explained how their 1999 hit 'Learn to Fly' was a deliberate attempt at an "AM Gold" - a 35-volume series of 1960s and 70s soft rock - track rather than the nu-metal that was popular at the time.
And the 50-year-old former Nirvana drummer believes the key to the 'White Limo' band's longevity has been being "disconnected" from what is popular in order to simply make the music they want to play.
He added: "We've just never been hip or cool; we just really haven't. I think that the reason why we're still here is because we do kind of disconnect ourselves from the popular stuff that's going on, but also because, what the f**k do we care? I just want to f***ing play music."