Roberts will line up at inside centre for Wales against England at Twickenham on Saturday, in the first of three World Cup warm-up games.
And the Cardiff Blues star has admitted that even though no silverware or title is on the line, the old-rivalry and world cup places is all the motivation the squad will need.
“There will certainly be no love lost because there’s no such thing as a trial England-Wales game,” said Roberts.
“Twickenham is sold out and boys are playing for World Cup places with the chance to realise dreams. It’s also a capped international and no player will disrespect that at all.”
“We couldn’t have asked for tougher opposition than England to help prepare for a World Cup.”