Ally Brooke says Tyga ''annihilated'' her song 'Low Key' ''in a good way''.

The 'Rack City' rapper was a last minute addition on the former Fifth Harmony star's latest single, but she credits the 29-year-old star for making the song what it is.

After revealing that ''magically, the stars aligned'' when Tyga came on board, the 25-year-old singer told Billboard's Pop Shop Podcast: ''I was blown away. He freaking annihilated that song in the best way possible ... He made the record so much better. He brought a new life to it.''

Ally had planned on pushing another single as her debut solo single instead of 'Low Key', but she just knew this was ''the one''.

She recalled: ''It was a pretty magical moment where I felt, 'this is it, I found her. I found the one!

''I was prepared with another single, so we were almost ready to hit the go button on that but... we couldn't get it perfect.''

The song was co-written by the likes of John Ryan, Teddy Geiger, and Julian Bunetta, and Ally was impressed from her first listen.

She said: ''My manager calls me and he's like, 'Ally, oh my gosh, I found this record. I just listened to it and it's incredible. All these amazing songwriters are a part of it. John Ryan, Julian Bunetta, Ian Kirkpatrick, Teddy Geiger. You need to hear it and if we can get it for you, it's going to be your single.'

''I was like, 'oh my gosh, that's amazing, let me hear it.' So he played it for me the next day and as soon as I got done with the first listen I was like, 'wow.'''

And it was a relief for Ally as she had spent ''months'' in the studio trying to come up with the right song.

She added: ''We all really just love (the song) and it feels like me, and that's what matters.''