Joe Schmidt insists selecting Robbie Henshaw for just his second-ever Test at full-back is a calculated gamble worth taking for Saturday's Six Nations opener against England.

Head coach Schmidt has selected Henshaw ahead of two-time Grand Slam winner Rob Kearney in a bold call to kick-start his side's title defence.

Henshaw made his name playing full-back at Connacht and won his first Ireland cap in the 15 shirt back in 2013, but has not featured there in his other 35 Tests.

Schmidt revealed British and Irish Lions centre Henshaw has been training at full-back behind the scenes with Ireland since last summer.

"Robbie trained last week and a bit in November at full-back," said Schmidt.

"He actually trained there a bit in Australia in the summer too. It's been an option for us for quite some time.

"Rob (Kearney) ran out of time a little bit. And we like the flexibility of Jordan Larmour on the bench covering a number of positions.

"It's one of those things that we've seen as an option for quite some time. So it's probably not as much of a surprise to Robbie or the team as it is to other people.

"We just felt the way he trained when we were away in Portugal, and the way he's trained this week, that it was worth pursuing. And maybe even as a longer-term option; when you go to a World Cup you need guys who are versatile in a squad of 31.

"It's probably a little bit of that as well as Robbie being a good player and a recognised full-back anyway."

Henshaw has flourished in the centres but has still expressed his desire for a return to the back-field, and must now cope with an expected aerial bombardment from England at the Aviva Stadium.

Schmidt insisted a greater risk than selecting Henshaw at full-back was to pick the 25-year-old at all, given the Leinster star has been battling back to full fitness after hamstring trouble.

"The greater risk for Robbie is lack of game-time, full-stop," said Schmidt. "He hasn't played that much himself."

Schmidt's other strong call has been to select Josh Van Der Flier at openside flanker ahead of the bullish British and Irish Lions flanker Sean O'Brien.

Leinster star O'Brien is fully fit after a broken arm suffered in the November win over Argentina but, unlike on previous occasions, Schmidt has resisted the temptation to pitch him straight into the Test match starting XV.

Van Der Flier excelled in November's stunning 16-9 win over New Zealand however, and has duly retained his starting berth.

Ireland team to face England in Dublin on Saturday: R Henshaw (Leinster), K Earls (Munster), G Ringrose (Leinster), B Aki (Connacht), J Stockdale (Ulster), C Murray (Munster), C Healy (Leinster), R Best (Ulster, capt), T Furlong (Leinster), D Toner, J Ryan (both Leinster), P O'Mahony (Munster), J Van Der Flier (Leinster), CJ Stander (Munster).

Replacements: S Cronin (Leinster), D Kilcoyne (Munster), A Porter (Leinster), Q Roux (Connacht), S O'Brien (Leinster), J Cooney (Ulster), J Carbery, J Larmour (both Leinster).