If I have a Legendary Skin Shard...

...will I get a guaranteed Legendary skin if I re-roll it with two common skins? Re-rolling one Epic or Legacy skin shard with two commons always gave me an Epic or Legacy, but wanna know yes or no for sure before I go and roll away a Legendary. Even if it's for a champ I never use, I'd rather have it than roll it for a common that I would use.