With Mike Phillips away with the British & Irish Lions the pair will battle it out to be Wales' first-choice No.9 during the two-Test tour next month.
Both will be 23 by the time the tour starts and with France-based Phillips 31 later this year Williams admits it is a good chance for either youngster to steal a march on the other.
"Me and Tav are good friends and we enjoy training alongside each other, but we will be pushing each other to make an impact this summer," he said.
"I am ambitious and I know that all areas of my game can improve.
"I'm sure that the forwards will provide me and the rest of the backs with enough quality ball to really express ourselves.
"The Welsh lads who are with the Lions have had their work cut out in preparing for Australia.
"But I'm sure while we are in Japan they will be looking over their shoulders at us and taking a special interest in who is playing in their position."
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