Blake Lively and Ryan Reynolds are setting wheels in motion to try and have Justin Baldoni's defamation lawsuit thrown out.

According to new court documents, obtained by TMZ ... the A-list couple's lawyers informed a NYC judge of their plans to file a motion to dismiss the "It Ends With Us" director's complaint against them -- in which Baldoni claimed they, along with their publicist Leslie Sloane, coordinated a smear campaign against him.

As you know, Blake made similar claims against Justin and his team when she filed a legal complaint against her costar ... where she alleged he sexually harassed her while making their romance drama.

Still, Justin maintains Blake's complaint and subsequent lawsuits have cherry picked messages between them in order to misrepresent their working relationship.

He has also claimed Blake and her husband tried to force his agency, WME, to drop him amid the feud ... though, WME has denied this claim.

While Blake and Justin's trial isn't expected to begin until March of next year, both camps have made it clear they're open to consolidating the 2 separate cases.

Yet, the next step in the "It Ends With Us" legal saga will take place on Monday ... when Justin's lawyer, Bryan Freedman, will have to defend his out of court antics, which Blake and Ryan's team has claimed could prejudice future jurors.

We're sure more developments are to come ... so, stay tuned!!!