The opinion of the court was delivered by: Justice Thomas
 Docket No. 94823-Agenda 12-September 2003.
 This case presents the question of whether defendant's constitutional right to be present at his guilty plea hearing was violated when the circuit court accepted his plea via closed circuit television. Under the facts presented by this case, we hold that it was.
 On March 23, 1998, defendant, Bennie Stroud, entered a negotiated plea of guilty in the circuit court of Kankakee County to the offense of possession of a stolen motor vehicle (625 ILCS 5/4-103(a)(1) (West 1998)), case No. 97-CF-621. When defendant entered his plea, he was not physically present in the courtroom; rather, he appeared via closed circuit television. Defendant was represented by counsel at the time the plea was taken, and defendant made no objection to his absence from the court or to the fact that the plea was taken through closed circuit television. Pursuant to agreement, defendant was sentenced to two years' probation. Before accepting the plea, the court advised defendant that any wilful violation of his probation could result in revocation, with a prison sentence of between three and seven years imposed. Following acceptance of the plea, the court advised defendant of his appeal rights, including the necessity of compliance with the requirements of Supreme Court Rule 604(d) (188 Ill. 2d R. 604(d)).
 On July 1, 1998, the State filed a petition to revoke probation, alleging that subsequent to the above-mentioned case, defendant committed the offense of unlawful possession of a controlled substance, as reflected in case No. 98-CF-374. *fn1 On November 3, 1998, defendant was found guilty of unlawful delivery of a controlled substance (720 ILCS 570/401(d) (West 1998)), case No. 98-CF-374. On December 1, 1998, defendant's probation for his initial conviction in No. 97-CF-621 was revoked because of the subsequent offense, and defendant was sentenced to seven years in prison for each offense, the sentences to run concurrently. Thereafter, defendant appealed the conviction in No. 98-CF-374 and the probation revocation in No. 97-CF-621. The appeals were consolidated.
 The appellate court dismissed defendant's direct appeal in No. 97-CF-621 for lack of jurisdiction, finding that because defendant had not filed a timely motion to withdraw his guilty plea pursuant to Rule 604(d), he could not attack the guilty plea in the appeal of his probation revocation. People v. Stroud, Nos. 3-98-0981, 3-98-0982 cons. (2000) (unpublished order under Supreme Court Rule 23).
 On November 22, 2000, defendant filed a post-conviction petition, again arguing that the original guilty plea should be vacated because he entered it via closed circuit television, rather than in person. The State filed a motion to dismiss, arguing that because defendant had not filed a timely motion to withdraw the guilty plea in No. 97-CF-621, he was barred from moving to vacate the plea through his post-conviction petition. The trial court granted the State's motion to dismiss, and defendant appealed.
 On review, the appellate court vacated both convictions and remanded for further proceedings in No. 97-CF-621 and for resentencing in No. 98-CF-374. 333 Ill. App. 3d 416. The appellate court found that, although defendant was barred from challenging his guilty plea on direct appeal, nothing prevented him from collaterally attacking his plea in a post-conviction proceeding on constitutional grounds. 333 Ill. App. 3d at 419. The court then found that defendant's plea of guilty over closed circuit television violated his constitutional right to be present at a critical stage of the proceeding. 333 Ill. App. 3d at 419.
 We allowed the State's petition for leave to appeal (see 177 Ill. 2d R. 315) and now affirm the appellate court.
 The State initially argues before this court that defendant waived his right to challenge his guilty plea. It notes that defendant did not file a motion to withdraw his guilty plea and vacate the judgment as is normally required by Rule 604(d) to bring an appeal. Relying on the rule that " ` "a constitutional right, like any other right of an accused, may be waived, and a voluntary plea of guilty waives all errors or irregularities that are not jurisdictional" ' " (People v. Peeples, 155 Ill. 2d 422, 491 (1993), quoting People v. Del Vecchio, 105 Ill. 2d 414, 433 (1985), quoting People v. Brown, 41 Ill. 2d 503, 505 (1969)), the State maintains that defendant cannot attack his guilty plea for the first time in a post-conviction proceeding.
 In response, defendant argues that he can attack his guilty plea in a post-conviction petition even though he did not first move to withdraw the plea or attempt to file a direct appeal because the plea itself was not voluntary. Specifically, defendant contends that the plea was involuntary because he was not advised of his right to be physically present in the courtroom at the plea proceeding.
 We agree with defendant that the State's waiver arguments must be rejected. " `Waivers of constitutional rights not only must be voluntary but must be knowing, intelligent acts done with sufficient awareness of the relevant circumstances and likely consequences.' " People v. Johnson, 75 Ill. 2d 180, 187 (1979), quoting Brady v. United States, 397 U.S. 742, 748, 25 L. Ed. 2d 747, 756, 90 S. Ct. 1463, 1469 (1970). Thus, a guilty plea does not waive a contention that the plea itself was involuntary because of faulty admonishments. People v. Gosier, 145 Ill. 2d 127, 141-42 (1991); People v. Beronich, 334 Ill. App. 3d 536, 540 (2002). Moreover, such claims may be raised for the first time in a post-conviction petition. Beronich, 334 Ill. App. 3d at 540. As we will explain more fully below, this case involves whether and to what extent a trial judge must admonish a defendant of his right to be physically present prior to accepting a guilty plea by closed circuit television. Accordingly, we conclude that the State's waiver arguments do not apply.
 We now turn to the merits of the question of whether defendant had a constitutional right to be physically present at the guilty plea hearing and whether his physical absence requires that his guilty plea be vacated. To support his position, defendant relies upon People v. Guttendorf, 309 Ill. App. 3d 1044 (2000), where the appellate court vacated a defendant's guilty plea because he was not physically present in court for the plea proceeding, but instead appeared by closed circuit television. Defendant attempts to distinguish this court's recent decision in People v. Lindsey, 201 Ill. 2d 45 (2002), on the basis that it involved an appearance by closed circuit television at an ...