The Welsh model and wife of Gary Lineker will guest star as an investigative journalist in the crime drama starring Emilia Fox, reports The Sun.
The role will be Bux's dramatic debut on television, having previously appeared on the likes of Hell's Kitchen and Loose Women.
Last week, Lineker had tweeted about his wife's acting role, saying: "Got man flu. And no Mrs L around to give me the sympathy that women are always so generous with at these times.
"Danielle Bux is not here in Mallorca as she is filming an episode of Silent Witness. Nothing untoward!"
Silent Witness will return for a 16th series on BBC One in 2013.
Digital Spy spoke to Silent Witness stars Emilia Fox and Tom Ward about the previous series earlier this year.