The 22-year-old Le Brocq has previously raced under the Erebus Academy banner in the team's GT3 cars and for other outfits in the Dunlop Series.
“I'm still pinching myself to be honest and can't thank everyone enough at Erebus for giving me this opportunity,'' said Le Brocq.
“I'm absolutely stoked. I don't think I've ever looked forward to a seat fitting as much as this and I'm really excited to be driving with Ash.
“It'll be great to get some laps in the car during the co-driver practice sessions at Perth next weekend and the other rounds in the build-up to the enduros.
“It's been my aim for a while to gain a V8 Supercars drive and this is a significant stepping stone towards pushing for a full-time drive in the category further down the track.''
Erebus owner Betty Klimenko is confident that Le Brocq is ready to step up to the intensity of the Pirtek Enduro Cup competition.
“Jack has been a part of the Erebus Academy program for a number of years and it's been great to see him develop as a driver and as a person to get to the point where he is today,” said Klimenko.
“We feel Jack has earned the chance to test himself in V8 Supercars and is ready to make the most of this opportunity driving with Ash.
“It's great that on one side of the garage we will have a team of up and coming drivers in Ash and Jack and then on the other side we've got the experience of Will and Alex Davison so I'm really excited about this year's enduros.''
Le Brocq is present with Erebus at Queensland Raceway today but is not permitted to cut laps as it is a rookie test for Walsh.
The test marks the first time that Walsh has run with the engine upgrade package debuted by team-mate Davison last month at Albert Park.
Walsh meanwhile says he is pleased to see Le Brocq be given an opportunity to race in the enduros, having made his own debut with Dick Johnson Racing in 2013.
“It's good to see Jack get the opportunity as I know from my own experience how hard it is for young drivers to get their first gig in the main game,” he said.
“It's good to be racing with someone like Jack, he's done lots of kilometres in the Development Series and has been going well.
“For me, it's really important to have a driver that getting lots of miles and to be race ready when the enduros come around.''