In the belt of Orion, the three stars that form the distinctive "belt" are not planets but rather stars. The two stars you are referring to are Alnitak and Mintaka. They are both blue supergiant stars, and their color may appear slightly different to the naked eye. Alnitak is the easternmost star in the belt and appears slightly bluish, while Mintaka, the westernmost star, appears slightly more yellowish-orange. The middle star in the belt, known as Alnilam, is the brightest of the three and appears bluish-white. These stars are part of the Orion constellation, and they are much larger and more luminous than any planet visible from Earth.