  We report the discovery of eclipses by circumstellar disc material associated
with the young star PDS 110 in the Ori OB1a association using the SuperWASP and
KELT surveys. PDS 110 (HD 290380, IRAS 05209-0107) is a rare Fe/Ge-type star, a
~10 Myr-old accreting intermediate-mass star showing strong infrared excess
(L$_{\rm IR}$/L$_{\rm bol}$ ~ 0.25). Two extremely similar eclipses with a
depth of ~30\% and duration ~25 days were observed in November 2008 and January
2011. We interpret the eclipses as caused by the same structure with an orbital
period of $808\pm2$ days. Shearing over a single orbit rules out diffuse dust
clumps as the cause, favouring the hypothesis of a companion at ~2AU. The
characteristics of the eclipses are consistent with transits by an unseen
low-mass (1.8-70M$_{Jup}$) planet or brown dwarf with a circum-secondary disc
of diameter ~0.3 AU. The next eclipse event is predicted to take place in
September 2017 and could be monitored by amateur and professional observatories
across the world.
