The divorce battle between Slash and his estranged wife Perla Ferrar has taken an unexpected turn. The Guns N' Roses guitarist has allegedly accused Ferrar of bigamy in an attempt to avoid paying his former spouse half of his earnings accumulated throughout their 13-year marriage.

Slash, 51, reportedly argues that his marriage to Ferrar in 2001 was not valid as she was still married to Carlos Marty, whom she wed in 1993. According to TMZ, Ferrar filed for divorce from Marty just one month after tying the knot but the papers were not filed correctly.

Both Ferrar and Slash, real name Saul Hudson, were under the assumption that she was single at the time of their marriage. However, the couple reportedly realised her divorce from Marty did not go through during a search for documentation when trying to obtain dual citizenship for their son Cash.

The couple are said to have hired a new lawyer in 2009 to finalise her divorce from Marty. Ferrar allegedly claims that the judge issued a decree nisi retroactive to 1994, the original date of her separation from Marty. However, Slash argues this was not the case.

TMZ reveals that the "putative spouse" legislation could apply to Ferrar and Slash meaning even though there are irregularities in the legal documents, they still considered themselves married so Ferrar could be entitled to some of the rocker's earnings.

Slash filed for divorce from Ferrar in 2014 citing irreconcilable differences and has requested joint physical and legal custody of their two sons, London, 13, and Cash, 11. It was the second time the guitarist had attempted to divorce Ferrar, after filing papers in 2010 before briefly reconciling with the music manager.

Addressing the financial situation given the couple did not sign a prenuptial agreement, Ferrar told TMZ in 2015: "I don't know how any of that's gonna work, but I know he's gonna do the right thing for me and his children as I would do the right thing to him." She added at the time: "Everything's really cool and amicable. [Slash and I] had a really long, lasting loving relationship for a long time. We're best friends, we're business partners and we just want to do what's best for our kids."

Guns N' Roses Slash
Guns N' Roses guitarist Slash is allegedly trying to block his estranged wife Perla Ferrar from receiving half of his earnings throughout their 13-year marriage GEORGES GOBET/AFP/Getty Images