They were two of the biggest tennis stars of their day: Aaron Williams, a hyper-malcontent American bad boy, and Charles Poole, a dim-witted prodigy who carried England’s hopes for a championship on his shoulders. Starring Andy Samberg (“Brooklyn Nine-Nine,” “Saturday Night Live”) as Aaron Williams and Kit Harington (“Testament of Youth,” HBO’s “Game of Thrones”) as Charles Poole, the HBO special presentation 7 DAYS IN HELL debuts SATURDAY, JULY 11 (10:00-10:45 p.m. ET/PT).