maybe she's playing air ukulele and the guy on the right is doing all the work...
LOL, you mean like she's MIMICKING the 'perfomance'?
Well, it's typical for performers in this style of music to lip-sync the ENTIRE performance, as well as the rest of the band mime their playing while a recording of the song is what actually gets blasted out the PA.
I'm not fabricating this, MANY of them have admitted it in interviews, (e.g. Britney Spears, Katy Perry, Janet jackson, Miley Cyrus, Rihannaa, etc), and they 'claim' that all the vigorous dance gyrations make it nearly impossible to sing while doing wild aerobic dance moves - that head-worn mic? yeah, that's a prop.
Seen it IN-PERSON many times myself back in the 80's and 90's at various shows.
So I'd really doubt she actually PLAYS the instrument in concert, but that does not answer if she CAN play an instrument for real.
That question in unanswered.