Kate Hudson Says She Was Told She's Too Old to Start Singing Career at 45

Kate Hudson is launching her music career at the ripe age of 45 -- and to anyone who's doubting her, she's got choice words ... basically, the verbal equivalent of flipping the bird.

The actress opened up about her pivot into singing -- with a whole debut album coming out this May -- during an interview with CBS's "Sunday Morning" ... where she dished on the brutal feedback she once received on the notion of diving into music as a non-20-something.

She says ... "There was someone who said to me -- and it kind of jarred me a little -- it was when I was in my early 30s, and they basically said, ‘It’s done, it’s passed. You can’t, you’re too old.’ And you know, for me, it wasn’t just about being a performer, it was about wanting to write music."

While the advice resonated with her for a bit ... she ultimately decided to move forward with creating an album anyway -- figuring she might as well try, 'cause why not?

Sounds like KH was defiant, adding ... "I was like, ‘Eh, f*** you.’ No, no one tells me what to do." She says this in a light-hearted way -- but you can tell she meant it ... 'cause she's all in now.

Kate's transition into music isn't coming out of nowhere -- she comes from a musical family, and she's even sung on camera in movies ... specifically, "About Adam" and "Nine."

It also seems Kate's new music venture has brought her somewhat closer to her estranged father, Bill Hudson, the vocalist for The Hudson Brothers.