Actor Fred Willard's cause of death has been revealed.

The beloved star with a long list acting credits – including "Best in Show," "This is Spinal Tap" and "Everybody Loves Raymond" – died of cardiac arrest, according to his death certificate. He was 86.

The document, obtained by TMZ, shows that the actor died on May 15 at 6:45 p.m.

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Fred Willard, the beloved star with a long list of acting credits including “Best in Show,” “The Spinal Tap” and “Everybody Loves Raymond,” died of natural causes in May at age 86.

Fred Willard, the beloved star with a long list of acting credits including “Best in Show,” “The Spinal Tap” and “Everybody Loves Raymond,” died of natural causes in May at age 86. (Richard Cartwright/ABC via Getty Images)

His daughter, Hope W. Mulbarger, was listed as the informant. She previously confirmed his passing to Fox News in a statement, stating that he died "peacefully."

"He kept moving, working and making us happy until the very end. We loved him so very much!" Mulbarger told us at the time. "We will miss him forever."

The document confirms the Ohio native was buried in Forest Lawn Memorial Park in Los Angeles. It also lists he had underlying conditions of coronary artery disease and myelodysplastic syndrome.

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Willard's acting career spanned five decades. He got his start in Chicago's renowned Second City sketch comedy troupe before becoming a familiar face on the small screen — appearing on "Get Smart," "Love, American Style" and "The Bob Newhart Show," among others.

Fred Willard died of a heart attack, his death certificate reveals.

Fred Willard died of a heart attack, his death certificate reveals. (AP)

He recently completed his Emmy-nominated recurring role on "Modern Family" and can be seen later this month in his recurring role as Steve Carrell's dad in the Netflix series "Space Force."

His other television credits include roles on "Roseanne," for which he was nominated for an Emmy, and "Everybody Loves Raymond," which earned him two Emmy nominations. Willard also appeared on "The Tonight Show with Jay Leno" more than 90 times.

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Willard is best known for his work in the comedies "Best in Show," "For Your Consideration" and "A Mighty Wind," in addition to "This is Spinal Tap," "Austin Powers," "Anchorman" and "Harold & Kumar Go to White Castle."