The Belgian will receive support from a host of BMC climbers in the 205 kilometre race features three ascents of the finishing climb, the Mur de Huy, a 1.3km 'wall' that averages 9.3 percent.
Gilbert, who finished fifth on Sunday at Amstel, won the Ardennes Classic in 2011 and finished third last year.
Brent Bookwalter, Steve Cummings, Mathias Frank and Amaël Moinard will be the support cast for the man in the rainbow jersey.
Joaquim Rodriguez, the winner last year following successive second place finishes, suffered a crash during Amstel Gold and is unlikely to be at full power and although compatriot Alberto Contador is in the line-up, that is seemingly under duress from his Saxo-Bank team.
He may well play a support role for Amstel winner Roman Kreuziger and Nicki Sørensen.
Team Saxo-Tinkoff sports director Philippe Mauduit said: "We go in Fleche with three free riders in Roman, Alberto and Nicki, and these three must be protected throughout the race, so they come unscathed to the final.
"But I think despite Roman's stunning victory in the Amstel, the Mur de Huy suits simply other great riders better, but that does not mean that we have no hope of winning."
'Purito' Rodriguez did a two hour training ride on Tuesday to confirm his participation but was downbeat on his chances.
"I will take part in La Fleche Wallonne with the number one on my back and that gives me strong motivation - but I’m also aware I’m not in my top shape and so it will be very hard to replicate last year's victory," he said. "I hope to recover my top shape for Liege-Bastogne-Liege."
Alejandro Valverde, the 2006 champion, and Nairo Quintana are likely to carry Spanish hopes while the figure of Peter Sagan lurks.
The Slovakian showed some fatigue when he finished 36th in Amstel Gold because of severe cramps but will look to finish a spectacular spring - which also includes wins in Gent-Wevelgem and Brabantse Pijl plus second place finishes in Flanders and Milan-San Remo - with another victory.
Michael Albasini stormed up the Mur de Huy to take second last year and will lead Orica-GreenEdge with Simon Gerrans resting ahead of Liege-Bastogne-Liege.
“We have plenty of confidence coming into Fleche,” said Albasini. “We rode great as a team at Amstel Gold, and we were able to stick to our plan well. Things are looking good for us for the next two Ardennes races.
“The final time up the Mur is a real killer. It’s a bit over one kilometre long, but it’s really steep with a maximum gradient of 26 percent.”
Richie Porte, who won Paris-Nice and was second at Criterium International and the Tour of the Basque Country, will feature for Team Sky alongside plus Sergio Luis Henao and Rigoberto Uran.
Michal Kwiatkowski, the young Pole who was fourth at Amstel, will lead Omega Pharma - Quick Step.
"We can count on Kwiatkowski who is in good condition and did well on Sunday, but we will see. With him every race is like a discovery — discovering new parcour, new race situations," OPQS sport director Davide Bramati said.
"For him it's an important test to learn again on this parcour. If there is the possibility for him to be in the front, for sure we will help him out to be there and get a good result."
Jelle Vanendert, Carlos Betancour, Igor Anton, the Garmin duo of Daniel Martin and Ryder Hesjedal, Lampre pair Diego Ulissi and Damiano Cunego plus Bauke Mollema and Enrico Gasparotto are others who could feature at the business end of the 77th edition of the race which features a new starting location in Binche, 20km west of Charleroi, which has been the starting city since 1998.
Most wins - Riders
3 Marcel Kint BEL 1943, 1944, 1945
3 Eddy Merckx BEL 1967, 1970, 1972
3 Moreno Argentin ITA 1990, 1991, 1994
3 Davide Rebellin ITA 2004, 2007, 2009
2 Ferdi Kübler SUI 1951, 1952
2 Stan Ockers BEL 1953, 1955
2 Rik Van Steenbergen BEL 1949, 1958
2 André Dierickx BEL 1973, 1975
2 Bernard Hinault FRA 1979, 1983
2 Claude Criquielion BEL 1985, 1989
2 Laurent Jalabert FRA 1995, 1997
Most wins - Countries
1 United States
Last 10 years
2012 Joaquim Rodríguez (ESP) Michael Albasini (SUI) Philippe Gilbert (BEL)
2011 Philippe Gilbert (BEL) Joaquim Rodríguez (ESP) Samuel Sánchez (ESP)
2010 Cadel Evans (AUS) Joaquim Rodríguez (ESP) Alberto Contador (ESP)
2009 Davide Rebellin (ITA) Andy Schleck (LUX) Damiano Cunego (ITA)
2008 Kim Kirchen (LUX) Cadel Evans (AUS) Damiano Cunego (ITA)
2007 Davide Rebellin (ITA) Alejandro Valverde (ESP) Danilo Di Luca (ITA)
2006 Alejandro Valverde (ESP) Samuel Sánchez (ESP) Karsten Kroon (NED)
2005 Danilo Di Luca (ITA) Kim Kirchen (LUX) Davide Rebellin (ITA)
2004 Davide Rebellin (ITA) Danilo Di Luca (ITA) Matthias Kessler (GER)
2003 Igor Astarloa (ESP) Aitor Osa (ESP) Alexandr Shefer (KAZ)