dissenting.
I am troubled by the court’s opinion. Without any discussion or analysis, the court states that the trial court implicitly found that good cause existed for the admission of testimony of an undisclosed witness. If we are to presume that the trial court found good cause when there is no express finding, we owe the bench and bar some guidance on this issue. Furthermore, the court agrees with the court of appeals that the trial court abused its discretion in allowing the testimony of the undisclosed witness and discusses at length the good cause exception. The court then states that it need not determine whether the erroneous admission of the evidence constituted reversible error because the error was waived. Since this case does not turn on whether or not there was good cause, the lengthy discussion on good cause is confusing and unnecessary. More important, however, is the court’s holding that the objection to the testimony of the undisclosed witness was waived. It is for these reasons that I dissent.
In order to put the issues before the court in proper perspective, a chronology of events is helpful. This case involved a bus accident that occurred in Mexico in 1979 which resulted in the deaths of two relatives of the petitioners (collectively referred to as “Clark”). The investigating officer was Hector Lira Morales (Lira) who concluded in his report that the cause of the accident was mechanical failure.
Suit was filed in September of 1980. In October of 1980, Transportes del Norte (TDN) served interrogatories on Clark seeking the names and addresses of “potential liability witnesses.” In 1981, Clark answered “I do not know” and that such information is “unknown.” In May of 1985, Clark filed supplemental answers to some of TDN’s interrogatories but filed no supplementation regarding the disclosure of potential liability witnesses. Less than a week prior to trial, on August 27, 1986, Clark filed additional supplemental answers which did not identify Lira as a witness with knowledge of relevant facts; however, the answers referred to “Exhibit 9 to Javier Plascencia Rodriguez’ deposition.” This exhibit allegedly consists of over fifty different documents which were written in Spanish and attached to a deposi*649tion taken by Clark. The exhibit was not introduced into evidence and it was not made part of the record. Lira’s name is supposedly somewhere among these documents.
Approximately a week before trial, TDN’s attorney was informed by Clark’s attorney that they intended to call a secret witness who had never been disclosed in answer to interrogatories. Clark’s attorney refused to disclose the name of the witness, yet agreed to produce the witness at a deposition on Labor Day, 1986, the day before the trial.
On August 29, 1986, TDN filed a motion for sanctions under Tex.R.Civ.P. 215(5) in which it asked the trial court not to permit any witness to testify who had not been revealed in response to TDN’s interrogatories. On September 2, 1986, the trial court held a hearing on the motion which was specific to Lira, the previously undisclosed witness. Without a showing of good cause by Clark for failure to supplement their answers to the interrogatories in question, the trial court denied the motion for sanctions and ruled that he would allow Lira to testify. Trial commenced the next day and for more than a year's wages as his fee, Lira testified that the accident was caused by excessive speed. The trial court rendered a judgment on the verdict in favor of Clark.
The court of appeals held that the trial court abused its discretion in allowing the undisclosed witness to testify. The majority agrees with the court of appeals on this issue, however, it reverses the judgment of the court of appeals on the basis that this error was not preserved. I strongly disagree that TDN failed to preserve any complaint as to the erroneous admission of Lira’s testimony.
It is important to emphasize the time frame in which the relevant sequence of events occurred. The pre-trial hearing, during which the motion to exclude Lira s testimony was argued and ruled on, occurred the same day the jury was empaneled. On the next day, trial commenced and Lira was the first to testify. Thus, this is not a situation in which a party makes a general pre-trial motion to exclude testimony of undisclosed witnesses and months later, when trial finally takes place, fails to object to the admission of such testimony.
Despite the fact that TDN urged the trial court to exclude Lira’s testimony one day before he testified, the court today adopts an inflexible rule and states that because the objection was not reiterated when the witness was called, error was not preserved.1 A review of Rule 52(b) of the Texas Rules of Appellate Procedure offers some guidance and supports my belief that the court is in error.
Rule 52(b) provides in part:
When the court hears objections to offered evidence out of the presence of the jury and rules that such evidence be admitted, such objections shall be deemed to apply to such evidence when it is admitted before the jury without the necessity of repeating those objections.
Tex.R.App.P. 52(b).2 In the context of this rule, I believe that the instant case is anala-gous and submit that the court heard an “objection” to Lira’s testimony in the form of a motion for sanctions, after which it “ruled” that Lira would be allowed to testify. Although TDN did not technically object to the introduction of Lira’s testimony when such was offered, the motion urged the day before should have relieved TDN from having to reurge its Rule 215(5) argument.
I believe the court goes astray in treating the motion for sanctions as a motion in limine. They are not the same. The trial court did not reserve ruling on the motion until some point during trial should the *650issue have arisen and an objection been raised, as is the procedure with regard to motions in limine. See Hartford Accident & Indem. Co. v. McCardell, 369 S.W.2d 331, 335 (Tex.1963); Union Carbide Corp. v. Burton, 618 S.W.2d 410, 415 (Tex.Civ.App.—Houston [14th Dist.] 1981, writ ref d n.r.e.).
Finally, to obtain reversal of a judgment based upon error of the trial court in admission or exclusion of evidence, the following must be shown: (1) that the trial court did in fact commit error; and (2) that the error was reasonably calculated to cause and probably did cause rendition of an improper judgment. Bridges v. City of Richardson, 163 Tex. 292, 354 S.W.2d 366, 368 (1962); Tex.R.App.P. 81(b). In this connection, the court agrees with the court of appeals that it was error to admit Lira’s testimony. Clark engaged in unsavory discovery tactics and sought to benefit from them. Because Lira was the only liability witness Clark produced at trial, the erroneous admission of his testimony was reasonably calculated to cause and probably did cause the rendition of an improper judgment.
In conclusion, I see no need to adopt an inflexible rule which gives deference to form over substance. As in this case, where an undisclosed witness is the first to testify after a ruling on a motion for sanctions, and the parties and the trial court were aware of the intention to call the witness, the objecting party should not have to reurge its Rule 215(5) argument in order to preserve error. Having two sets of rules to preserve objections is another trap for lawyers. The unnecessary rigidity of the court’s opinion results in an injustice in this case. Also, since the court announces a new rule, it should not be applied retroactively.
The court of appeals was correct in reversing and remanding the cause for a new trial. Thus, I would affirm the judgment of the court of appeals.
. Neither of the cases cited by the court involved a pre-trial motion which specifically sought to exclude testimony of a particular undisclosed witness. See Security Ins. Co. v. Nasser, 755 S.W.2d 186 (Tex.App.—Houston [14th Dist.] 1988, no writ); Greenstein, Logan & Co. v. Burgess Mktg., Inc., 744 S.W.2d 170 (Tex.App.—Waco 1987, writ denied).
. Rule 103 of the Texas Rules of Civil Evidence was recently amended to include this sentence. 33 S. Goode, O. Wellborn & M. Sharlot, Texas Practice § 103.1 (1988).