STAMFORD, Conn. - Former football player and professional wrestler Jim (The Anvil) Neidhart, who won two world tag-team titles over his World Wrestling Entertainment career, has died. He was 63.

The WWE confirmed his passing Monday in a statement on its website. There was no immediate word on the cause of death.

Neidhart, a native of Tampa, Fla., played with the Oakland Raiders and Dallas Cowboys before turning to pro wrestling. Trained by WWE Hall of Famer Stu Hart in Calgary, Neidhart achieved his greatest success in the ring as a tag team with brother-in-law Bret (Hit Man) Hart.

“Stunned and saddened. I just don't have the words right now,” Hart posted on Twitter along with a photo from their championship heyday.

Known for their striking pink and black outfits and no-nonsense style, Neidhart and Hart held the tag belts for nearly a year after beating The British Bulldogs in early 1987. They enjoyed another long reign as champs after defeating Demolition in mid-1990.

Neidhart also teamed with Bret's younger brother, Owen, and wrestled in singles competition. The two Hart brothers joined Neidhart, Davey Boy Smith and Brian Pillman in a re-formed Hart Foundation faction that enjoyed a strong run in 1997.

After leaving WWE later that year, Neidhart had a brief run in then-rival World Championship Wrestling. His daughter, Natalya, currently wrestles in WWE.

There was no immediate word on funeral arrangements.