Porte competed in the final race of the Ardennes Classics previously with Team Sky in 2014 and 2013, failing to finish the race in each attempt. He'll join BMC's team from Flèche Wallonne for Sunday's monument.
"I'm coming in off the back of altitude camp and my last block of stage races, so Liège-Bastogne-Liège will be a good chance to test the legs on these climbs," he said. "I've only lined up twice before so I'm not going in with any real expectations."
Samuel Sanchez, sixth during Wednesday's Flèche Wallonne, will also start Liege, as will 2011 winner Philippe Gilbert, although he has been suffering from the ill-effects of a broken finger and finished 91st on Wednesday.
Team director Valerio Piva said the team is going in with multiple options.
While acknowledging the current good form that led to his Flèche Wallonne finish, Sanchez said matching that result at Liege will be a taller order.
"Liège-Bastogne-Liège is going to be really tough," he said. "We're looking at six or more hours in the saddle and it looks like the conditions will be really bad, so we'll have to see on the day."