Nothing tells the world you're in love quite like a PDA-packed social snap. For celebrities, it's the ultimate way of giving their fans an inside view of their relationships and home lives. Everyone from Gisele Bündchen to First Lady Michelle Obama is getting in on the trend, sharing archived wedding photos, formative moments from the early days of lasting commitments, and more. A notable newcomer to Instagram, Jessica Simpson recently shared an intimate kiss with her future husband, Eric Johnson; and Channing Tatum took his followers into a fun photo booth session with his wife, Jenna Dewan. Keep reading to see the best PDA we've seen so far, and if you're in the mood to turn the heat up a notch, check out celebrities getting sexy on Instagram!