The Munster flanker was a surprise absentee from the Irish World Cup squad last autumn but after Keith Gleeson was ruled out of Saturdays last-day clash with Scotland with a broken arm, OSullivan turned to Wallace to fill the back-row vacancy.

It will be Wallaces first international appearance since a try-scoring outing in the final World Cup friendly against the Scots at Murrayfield which many thought had earned him a place on the plane to Australia.

Instead, Wallace found himself watching at home on television as Ireland advanced to the quarter-finals.

He may yet gain ample compensation for that disappointment though because if the Irish were to record a massive win against the Scots, victory for England over title favourites France in Paris could hand Ireland their first championship since 1985.

Even if the ultimate prize proves a step too far, OSullivans side should still register their first Triple Crown for 19 years and only their seventh of all time.

Lock Paul OConnell has recovered from his rib problem and replaces Donnacha OCallaghan, while skipper Brian ODriscoll becomes the third-quickest player in history to reach the 50-cap mark.

Ireland team to face Scotland in the RBS 6 Nations at Lansdowne Road, Dublin on Saturday:

G Dempsey (Leinster); S Horgan (Leinster), G DArcy (Leinster), B ODriscoll (Leinster, capt), G Murphy (Leicester); R OGara (Munster), P Stringer (Munster), R Corrigan (Leinster), J Hayes (Munster), S Byrne (Leinster), P OConnell (Munster), M OKelly (Leinster), S Easterby (Llanelli), D Wallace (Munster), A Foley (Munster).

Replacements: F Sheahan (Munster), Marcus Horan (Munster), D OCallaghan (Munster), V Costello (Leinster), G Easterby (Rotherham), D Humphreys (Ulster), K Maggs (Bath).