Travis Scott and Kylie Jenner aren't together anymore, but she still lives rent-free in his music ... at least judging by a new song lyric that mentions Kylie's exact boob size.

In a feature on Don Toliver's new track "Rosary," Travis raps, "She look at me like Scotty, man, that S on my chest / Forty-four five C, the way they sit, I need to test".

Those measurements match exactly what Kylie shared as the boob size she got when she went under the knife.

As we reported ... a fan begged the mom of 2 for the secret to her "perfect" natural-looking D to DD-sized boobs.

Kylie responded by posting, "445 cc, moderate profile, half under the muscle!!!!! silicone!!!"

She also shouted out her surgeon, Garth Fisher.

Kylie has, of course, moved on since her 2022 split from Travis. She's been getting serious with Timothée Chalamet.

No word on how Kylie feels about the lyrics, but it might be more interesting to get Tyla's thoughts. She's who Travis is rumored to be dating lately.