Will a 50mm "FD" fit my 5D classic?

I have a 5D classic and am trying to put a portrait lens onto it for nothing - unless I can find one for that, in which case I'll be happy to pay that! But seriously, I have found a Canon 50mm FD lens on Craigs List and want to know if the FD lenses will fit my 5D. Do I need to invest in an adapter? If so, is there a different adapter ring which would avail me more or better options for getting inexpensive glass on my camera?

I hate being cheap but I'm learning and don't have any cash either so there it is.

Btw, the lens I use all the time is a 70/200 is usm 4.5, so you can see how indoor and portraiture are not easy with that setup.

Thanks in advance for your thoughts,

Rusty

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Rusty Halverson Corona CA