How to cue session during live performance

[llamallover]

Hi all.

I am wondering if there is a way to do the following:

1) play live a song on electric piano
2) cue a Pro Tools session to play backing tracks that begin mid-way through the song

Obviously I wouldn't be able to physically hit play in the middle of the song because both hands will be occupied on the piano.

Maybe there is a midi controller of some sort activated via a foot pedal system?

Thanks in advance.

Matt