La Rochelle, who stunned four-time Champions Cup winners Leinster Rugby to clinch their maiden European crown last season, face a tough opener against TOP 14 champions Montpellier.

And having had their bid for a league and cup double ended by Stade Toulousain in last season’s play-offs, Ronan O’Gara’s side will be keen to add French top-flight honours to their Champions Cup success this time around.

La Rochelle's new signings include French international wing Teddy Thomas, Samoan utility back UJ Seuteni and Irish lock Ultan Dillane, but O’Gara’s shrewdest piece of business may be the recruitment of fly half Antoine Hastoy.

French international Hastoy, who joins from Section Paloise, is a reliable goalkicker, whose consistency could prove decisive in the coming season.

Montpellier have added Louis Carbonel and Leo Coly to an already star-studded half back department featuring Cobus Reinach, Gela Aprasidze, Paolo Garbisi and Louis Foursans.

Before that match, the TOP 14 season kicks off with Racing 92 hosting fellow Heineken Champions Cup side Castres Olympique.

Three-time European runners-up Racing were eliminated in the TOP 14 play-offs last season, while Castres finished runners-up to Montpellier.

The pair are both in Pool A in the Heineken Champions Cup but cannot meet each other until the knockout phase.

Racing’s recruits include French international forward Cameron Woki and South African full back Warrick Gelant.

Castres' star signing looks to be Fijian lock and 2018 EPCR player of the year Leone Nakarawa, who joins from RC Toulon.

Three-time Heineken Champions Cup ASM Clermont Auvergne open their TOP 14 season at Stade Francais.

Clermont’s new faces include Argentina wing Bautista Delguy as they begin ‘projet Clermont 2025′; a plan under which they hope to land the Champions Cup by 2025.

The opening weekend of TOP 14 is completed by Sunday’s clash between fellow Heineken Champions Cup sides Union Bordeaux-Bègles and Stade Toulousain.

The arrivals of Melvyn Jaminet and Ange Capuozzo give Toulouse plenty of options at full back, while scrum half Paul Graou could provide vital cover.

Bordeaux have signed wing Madosh Tambwe from South Africa’s Blue Bulls, while prop Ugo Boniface joins from Bayonne.

Heineken Champions Cup holders Stade Rochelais tomorrow begin their bid to add the TOP 14 title to their trophy haul when they host Montpellier Hérault Rugby.