The pair will join in May to work across all of the agency's business, with particular emphasis on Land Rover, Marks & Spencer and Virgin.
The duo, who join the agency as senior creatives, have worked at BBH for three years. Their recent output includes the Campaign Press Awards-nominated work for Zanussi, as well as the current BA.com poster campaign.
Ben Priest, the RKCR/Y&R executive creative director, said: "With a client list like ours, you have to keep recruiting the very best creative talent. Dan and Amber are exactly that. They've done great work wherever they've been, and we're delighted to have them at the agency."
Before joining BBH, Hubert and Casey were at DDB, where they worked on accounts including Heals and Volkswagen. While there, they also produced the VW "bollocks" viral, as well as the D&AD award-winning "fashion victims" campaign for Harvey Nichols.