The Leeds defender has been likened to American actor Tom Selleck after sporting the “Magnum, P.I” style moustache.
Roberts is unbeaten in eight Championship games with the Elland Road table-toppers since his January loan move from Burnley.
And the Wales full-back is praying his lucky facial hair can rub off on Robert Page’s Dragons, who host Poland in Tuesday’s play-off final in Cardiff, and inspire them to reach the finals in Germany.
Roberts laughed: “It’s just a little bit of a joke.
“My wife (Georgina) last year was like, ‘Why don’t you grow it?’ so I did and then we went on an unbeaten run at Burnley.
“I’ve done the same thing this year and keep asking her if I should shave it off but she likes it so I’m leaving it there.
“It’s played about 25 Championship games and never lost, so I hope that continues in the Championship and maybe it gives us a bit of luck on Tuesday night.
“It’s the power of the tache, isn’t it!”
But asked if he is superstitious, Roberts, 28, added: “I’ve met a lot of players who are like that but that’s not me. It’s a nice record.
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“I asked my wife, ‘Should I get rid of it?’ but she likes it and she’s the boss so I’ll leave it there.”
Roberts has scored one goal in nine games after linking up with Leeds at the start of the year.
Before that, he netted six times in 88 outings for Burnley.
But it was his time at Swansea where Roberts really caught the eye, scoring 11 goals in 152 matches for his boyhood club.