HBO has a released a trailer for 7 Days in Hell, a mockumentary about a fictional tennis match that went on for an entire week. Andy Samberg (The Lonely Island) stars as the scrappy underdog opposite Kit Harington (Game of Thrones) as a snobby Englishman. The special will feature several celebrity cameos including Fred Armisen, Will Forte, Lena Dunham, and actual tennis star Serena Williams.

From HBO’s official synopsis: “This sports ‘documentary’ brings together Andy Samberg and Kit Harington for a look back at a pair of fictional players from the not-too-distant past, who played the longest and greatest tennis match of all time: a seven-day, five-set marathon that took literally everything out of them. In addition to highlights (and lowlights) from the match, the special looks back at the lives and careers of the competitors: Aaron Williams (Samberg), a hyper-malcontent, and Charles Poole (Harington), a dim-witted prodigy who carried England’s hopes for a tennis champion on his shoulders.”

The match between Williams and Poole takes place during the Wimbledon tournament, whose rules do not allow tiebreakers during the final set: the winner must have at least a two-game margin of victory. By coincidence, a Wimbledon match currently holds the real-life record for longest tennis match at 11 hours 5 minutes spread out over 3 days. John Isner and Nicolas Mahut played the maximum five sets. Two sets went to tiebreakers before the fifth and final set, which went on for over 8 hours, before Isner finally emerged victorious 70-68. The next day, Isner lost to his next round opponent, Thiemo de Bakker, after just 74 minutes.

7 Days in Hell will debut online on July 8 and on HBO’s TV channel on July 11.