This is a simple song, I'm gonna write it for a friend
My shirt is inside out, I'm messy with the pen
He met Margaret on a rooftop, she was wearing white
And he was like, "I might be in trouble"
He had flashes of the good life, he was like
"Should I jump off this building now or do it on the double?"

[with Jack Antonoff:]
'Cause, baby, if your love is in trouble
Baby, if your love is in trouble
Baby, if your love is in trouble

When you know, you know
When you know, you know
It kinda makes me laugh, running down that path
When you're good, it's gold
'Cause when you know, you know

[Jack Antonoff:]
A word to all my friends
But there are red flags, they are not nice
There are black eyes and there are blue eyes
If you're asking yourself, "How do you know?"
Then that's your answer, the answer is "No"
Yeah, gotta run, gotta run around like your head's on fire
Run away like your head is on fire

[with Jack Antonoff:]
'Cause, baby, if your love is in trouble
Baby, if your love is in trouble
Baby, if your love is in trouble

[with Jack Antonoff:]
When you know, you know
When you know, you know
It kinda makes me laugh, running down that path
When you're good, it's gold
'Cause when you know, you know
When you're old, you're old
Like Hollywood in me, the diamond on your ring
The soul that you bring to the table
One that makes me see, eeh-eeh-eeh
In a minor key
'Cause when you know, you know
When you know, you know

So, if you don't know
Don't give up
'Cause you never know what the new day might bring

[with Jack Antonoff:]
Maybe tomorrow you'll know
Maybe tomorrow you'll know
Maybe tomorrow you'll know

I mean, join the party
By the way, the party is December 18
(Okay, let's waltz this out, 'cause)

[with Jack Antonoff:]
'Cause when you know, you know
When you're old, you're old
Like Hollywood in me, that diamond on your ring
The soul that you bring to the table

One that makes me see, eeh-eeh-eeh
In a minor key
Diamond on your ring
'Cause when you know, you know
When you know, you know