There are binary systems in globular clusters so if you can get multiple objects forming in one system, why not a gas giant and a star? The lack of metals is a big problem though since you seem to need heavier elements to form planets. Globular clusters have a fraction of the sun's heavy elements but there's still pulsars/neutron stars found in them so perhaps somewhere there might be a planet.

Of course what's the chances of a star (around which planets can form) forming from the gas of a supernova remnant in the crowded enviroment of a globular cluster?