https://cdnph.upi.com/ph/st/th/4671781178517/2026/upi/b2776327b230eba90e7648ec6318ee72/v1.5/Hugh-Laurie-Joe-Alwyn-join-Legacy-of-Spies-series.jpg" /> "House" alum Hugh Laurie and "The Favourite" actor Joe Alwyn have joined the ensemble of the BBC's espionage thriller, "Legacy of Spies."