Credit: WENN

Brian Austin Green is entering the lion's den of Charlie Sheen's Anger Management.

Brian — still probably best known from Beverly Hills 90210 and his marriage to Megan Fox — is joining the FX show as a series regular, Deadline reports. Brian, 39, will play Sean, Charlie's nemesis, who also happens to be the boyfriend of his ex-wife Jen (Shawnee Smith).

Brian's Sean actually made his first appearance on the series last season, but that was before the recent fallout with Selma Blair. The show is now looking for a "sexy" new love interest to replace her.

Here's how Entertainment Weekly describes the new female role being cast: "In the listing from the show’s casting director, the character is called 'the new doctor' and doesn’t have a name yet. The actress should be 'gorgeous' and 'sexy' (yes, both, not just one) and in her 30s or 40s. She is preferable Latina or Caucasian, between 5 and 5’6″ (Sheen is 5′ 9″). She’s further described as a 'by-the-book psychiatrist' who joins Charlie to co-author the sex study research he and Kate (Blair) were working on before she left the show. ... 'If Charlie and Kate were like Sam and Diane on Cheers, then you are Rebecca,' continues the description. 'Tough, career driven, neurotic and you wear your heart on your sleeve.' ... But there is also this: 'And you hate yourself for eventually becoming attracted to Charlie.'”

They should just cast one of Charlie's "goddesses" — or maybe Brian's wife? Charlie wanted Mila Kunis, but what about Megan Fox?

Sources: DeadlineE! News, Entertainment Weekly