Dick Van Dyke

Dick Van Dyke is undergoing tests for "cranial throbbing," according to the Associated Press.

The legendary actor, well-known for The Dick Van Dyke Show and Diagnosis Murder, has been suffering from throbbing in his head when he lies down that has caused him to lose sleep, a rep for the 87-year-old actor says. So far, no diagnosis has been made.

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His rep says Van Dyke is doing OK, but the "fatigue factor has become acute."

Until he is diagnosed and treated, Van Dyke has been advised not to fly, which is why he has canceled his trip to accept an award from New York's 92nd Street Y.