Gregg Allman, 64, Engaged To 24-Yr-Old Girlfriend

Perhaps the seventh time's the charm for Allman Brother's founding member, Gregg Allman.

The rocker revealed on Piers Morgan Tonight that he plans to give the institution one more shot-- this time with fiancée Shannon Williams, who is 40 years his junior.

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Williams, 24, joined her soon-to-be husband on the program as he promoted his new memoir, My Cross to Bear, and when asked what she might think of becoming wife number seven, he quickly rose to defend their May-December romance.

"That's not what she's becoming," he responded. "She's becoming wife number one. I don't have a wife. Haven't had one for years."

To further his point he added, "This time, I am really in love."

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Allman then appeared on CBS This Morning to again defend his relationship with Williams, calling it an "altogether different" experience than his previous wives because he is presently "sober."

Allman's past marriages include singer Cher (1975-1979) with whom they share one son, Elijah Blue Allman.