  We present evidence for a small glitch in the spin evolution of the
millisecond pulsar J0613$-$0200, using the EPTA Data Release 1.0, combined with
Jodrell Bank analogue filterbank TOAs recorded with the Lovell telescope and
Effelsberg Pulsar Observing System TOAs. A spin frequency step of 0.82(3) nHz
and frequency derivative step of ${-1.6(39) \times 10^{-19}\,\text{Hz} \
\text{s}^{-1}}$ are measured at the epoch of MJD 50888(30). After PSR
B1821$-$24A, this is only the second glitch ever observed in a millisecond
pulsar, with a fractional size in frequency of ${\Delta \nu/\nu=2.5(1) \times
10^{-12}}$, which is several times smaller than the previous smallest glitch.
PSR J0613$-$0200 is used in gravitational wave searches with pulsar timing
arrays, and is to date only the second such pulsar to have experienced a glitch
in a combined 886 pulsar-years of observations. We find that accurately
modelling the glitch does not impact the timing precision for pulsar timing
array applications. We estimate that for the current set of millisecond pulsars
included in the International Pulsar Timing Array, there is a probability of
$\sim 50$% that another glitch will be observed in a timing array pulsar within
10 years.
