Khushboo went to Judicial Magistrate S. Sreedharan's court in Mettur, 600 km southwest of Chennai, Tuesday to surrender but the magistrate was not present.
The actress then recorded her presence in the court register. "I came to surrender and will come to the court tomorrow (Wednesday)," she told reporters at the premises.
On Friday, Sreedharan had issued a non-bailable warrant against Khushboo for failing to appear in court in the defamation suit.
Khushboo had earlier filed an anticipatory bail application before the Madras High Court, fearing arrest.
Acting on this application, judge S. Sardar Zakharia Hussain reserved orders Tuesday after hearing arguments by the actress's counsel R. Asokan and A. Sirajudeen.
He heard counsel for A. Murugesan, who filed the complaint against the actress at the Mettur court in Salem district.
Judge Hussain said his order on the bail plea would come Wednesday.
The Mettur judge too is expected to give his order Wednesday.
Khushboo's friend, actress Suhasini, wife of noted director Mani Ratnam, who has been targeted by civil society groups for backing Khushboo, is now facing two cases filed against her by activists of the PMK, an ally of the central government.
The Tamil Nadu Nadigar Sangam (South Indian Film Artistes Association) has lambasted Suhasini for supporting Khushboo.
A few days ago, taking part in a film festival, Suhasini had apologised to Khushboo "on behalf of Tamils". On Tuesday, Suhasini reportedly sent a letter to the Sangam, explaining her position and remarks.
Several cases have been filed in lower courts in Tamil Nadu against Khushboo following her comments in an interview about the rising trend of pre-marital sex in the state. Khushboo had said in the interview that it was fine for girls to indulge in pre-marital sex as long as they took precautions.
Her remarks were widely criticised by political parties, which alleged she had hurt Tamil sentiments.