Demi Lovato Starts ‘Sorry Not Sorry’ House Party Tour with Rob Gronkowski in Boston

TMZ Staff

socastcmsRssStartTMZ StaffsocastcmsRssEndDemi Lovato had a great idea for a mini tour to promote her new song — house parties featuring local celebs … which she kicked off in Boston with Rob Gronkowski. Demi hosted a rager Tuesday at a pad she rented in Beantown, which was stop #1 in her…