¶1(concurring). I concur with the result of the majority opinion affirming the con*182viction in this case, but I would affirm the conviction on different grounds. The majority concludes that admission of Cathy Herman’s testimony was error, but that it was harmless error. I believe that admission of Herman’s testimony was not error, and I would affirm the conviction on that basis.
¶2The majority concludes that admission of Herman’s testimony was error because McClelland v. State, 84 Wis. 2d 145, 267 N.W.2d 843 (1978), prohibits impeachment of a witness by extrinsic evidence of collateral facts. The majority argues that this rule prevents confusion of issues, waste of time, and focus of attention on trivial matters. Generally, these concerns are valid and ought to prevent impeachment of a witness by extrinsic evidence on a collateral matter. However, when a criminal defendant testifies on direct examination that he or she has never committed any acts similar to the offense charged, these concerns are less valid. In such a case the defendant’s credibility is a central issue. Therefore, in the discretion of the trial court, extrinsic evidence ought to be admissible to contradict the defendant’s testimony.
¶3Justice Connor T. Hansen’s analysis of this issue in his dissenting opinion in McClelland, 84 Wis. 2d at 162-65 (in which I joined), applies to this case. Admission of Herman’s testimony to contradict the defendant’s statement that he never sought sex from anyone other than his wife did not confuse the issues, waste time, or focus attention on a trivial matter. The crime charged was not factually connected to the testimony of Herman. The two incidents occurred fourteen months apart. Therefore, admission of this testimony would not confuse the issues, waste time, or focus attention on a trivial matter because it focused attention on a critical matter — the defendant’s credibility. Here, the defendant testified on direct examination that he never sexually assaulted his niece and that he had never sought sex from anyone other than his wife. *183His credibility was crucial to a finding of guilt or innocence.
¶4In his dissenting opinion in McClelland, Justice Hansen also pointed out that admission of the extrinsic testimony did not unfairly surprise or prejudice the defendant. Here, as in McClelland, the defendant was not unfairly surprised by the admission of Herman’s testimony. The defendant himself raised the issue by stating on direct examination that he had never sought sex from anyone other than his wife. Herman’s testimony was probative of the defendant’s veracity in making that declaration. Therefore, her testimony was properly admitted.
¶5Section 906.08, Stats., was not intended to exclude evidence under these circumstances. The policies behind sec. 906.08 are not implicated when a defendant testifies, as in this case. The search for truth requires that the jury hear competent evidence relevant to the defendant’s credibility.
¶6In this case the defendant on direct examination stated that he never sought sex from anyone other than his wife. Under McClellandand section 906.08, Stats., the defendant was properly asked on cross-examination whether he had sought sex from Herman. The defendant denied ever .seeking sex from Herman. Under McClellandthe prosecutor was bound by that answer and was without recourse to show that the answer was false. This should not be so. If the prosecutor is bound by the defendant’s answer on cross-examination, the jury is denied evidence which is relevant to the defendant’s credibility, and the defendant has a “shield against contradiction of his untruths.” Walder v. United States, 347 U.S. 62, 65 (1954). Because the defendant’s credibility is an important issue when he testifies that he did not commit an offense, evidence of his credibility is important to a determination of the truth. Therefore, extrinsic evidence ought to be allowed, even on a collateral issue, when the defendant de*184nies engaging in any activity similar to the offense charged.
¶7The Second Circuit Court of Appeals in United States v. Benedetto, 571 F.2d 1246 (2d Cir. 1978), allowed extrinsic evidence to contradict the defendant’s testimony on a collateral issue. In Benedettothe defendant was charged with receiving money in connection with official duties as a government meat inspector. Id. at 1247. He testified on direct examination that he did not receive money in connection with his duties from the government’s witnesses or anyone else. Id. at 1248 (emphasis added). On cross-examination the defendant denied receiving money from Herman Lustgarten. Lustgarten testified in rebuttal that he periodically gave money to the defendant. Id. at 1248.
¶8The court in Benedettostated: “Once a witness (especially a defendant-witness) testifies as to any specific fact on direct testimony, the trial judge has broad discretion to admit extrinsic evidence tending to contradict the specific statement, even if such statement concerns a collateral matter in the case.” Id. at 1250. The court found the evidence to be admissible under Fed. R. Evid. 607 (the federal counterpart to sec. 906.07, Stats.) and upheld the conviction. Id. at 1251.
¶9A similar analysis should apply in this case. Here, the defendant testified on direct examination that he did not commit the sexual assault and that he never sought sex from anyone other than his wife. He testified on cross-examination that he never sought sex from Herman. Herman’s rebuttal testimony here is similar to Lustgar-ten’s testimony in Benedetto. Therefore, the trial court in this case should have the same discretion to admit Herman’s testimony as did the trial judge in Benedetto.
¶10I agree with the court in Benedettoand joined the dissent in McClellandwhich declares that extrinsic evidence may be admitted, in the discretion of the trial court, to *185contradict the testimony of a defendant as it relates to credibility. For the reasons stated in this concurrence, I believe that sec. 906.08, Stats., was not intended to preclude admission of this evidence.
¶11I am authorized to state that Justice Donald W. Steinmetz and Justice Louis J. Ceci join in this concurring opinion.
¶12(concurring). I join Justice Callow’s concurring opinion. Further, I would state that if the district attorney asks a question of the defendant regarding sexual infidelity, which as in this case was whether the defendant asked Cathy Herman for sexual activity, and the district attorney is bound by his negative answer, then the defendant’s attorney would necessarily ask that the district attorney’s question be stricken from the record and the jury instructed to disregard it. Standing by itself, the question and its content are without foundation and merely suggest prejudicial information. Even if the trial court would overrule the lack of foundation objection, the question would suggest to the jury that it would hear more on the subject. When it hears no more on the subject, it is impossible to predict whether that would redound to the prejudice of the defendant or the state. The defendant raised the subject of his sexual proclivity on direct examination and it was irrelevant at that time. Since it was heard and became evidence to be considered by the jury, the attack on its believability should be allowed.
¶13There is an issue of the nearness in time of Cathy Herman’s information to another event. The question is what event is the witness’s information to be related to in time. As I analyze it, the information is not related to the offense, since it is irrelevant to whether that event occurred. Rather, it is related in time to the defendant’s statement on direct examination; it is relevant to his *186credibility and is close in time to that event. Such an analysis is eminently fair to the defendant, since he raised the subject of his sexual fidelity to his wife and is best aware of his philanderings or attempts at it, if any have taken place. If there have been other recent transgressions or attempts at sexual infidelity close in time to his testimony, he would be well-advised not to try to impress the jury with his alleged fidelity which could be questioned.
¶14If the district attorney were not allowed to follow up his question with available information, an overzealous district attorney could ask a question inferentially loaded with prejudicial ideas and not be presently prepared to offer proof. The trial court would almost by necessity be required to hold an offer of proof hearing to make sure that the district attorney had follow-up evidence to the question in order to avoid an ethics problem and then not allow the jury to hear the information.
¶15I concur with the majority; however, I would find the foundation testimony of Cathy Herman permissible under sec. 906.08, Stats., since the defendant volunteered the subject on direct examination. He caused the subject to become relevant to his credibility, if not to the charged act of the offense.