Rule 801(d)(1)(B) of the Federal Rules of Evidence
Definition
Provides that a prior statement is not hearsay and is admissible if the declarant testifies and is subject to cross examination, and the prior statement is both consistent with the declarant’s current testimony and offered either to (1) rebut a charge of recent fabrication or improper motive or (2) rehabilitate the witness's credibility when attacked on other grounds.