Wiktionary
can't help
vb. Not able to avoid a situation, or stop something from happening.
Wikipedia
Can't Help
Can't Help is a song by the band Parachute.
Usage examples of "can't help".
I don't know if it's some weird kind of aesthetic thing or a psychological phobia, or maybe even a physical fact of its existence the way we can't help flinching if someone makes like to punch us, for instance and I don't care.