Uncapped Ulster duo, brothers Bryn and Zac Ward have been called up in their places and will depart for Sydney with the rest of the squad on Monday.

In one of the biggest success stories in Irish rugby in the last two seasons, O'Brien has played his way into Leinster and Ireland's starting 15.

James Ryan misses out through injury. 

Elsewhere, Jamison Gibson-Park will win his 50th Test cap in green, while uncapped Ulster scrum-half Nathan Doak is in line for his Ireland debut off the bench.

Handling errors and mistakes from England have been taken advantage of by Andy Farrell's side, who could not have wished for a better opening 40 minutes.