No. Although an object may be definite, it is not usually pre-posed if it is not pre-existent in the context.
Zhāng：Zuó tiān nǐ zài xiǎo wáng de shēng rì wǔ huì shàng ，kàn jiàn le nǎ xiē rén？
Zhang: Whom did you see at Xiao Wang’s birthday party yesterday?
Lǐ：Wǒ kàn jiàn le xiǎo dīng gēn xiǎo chén 。(Improper: xiǎo dīng gēn xiǎo chén ，wǒ kàn jiàn le。)
Li: I saw Xiao Ding and Xiao Chen.
(Although Xiao Ding and Xiao Chen can be considered definite, they should not be pre-posed because they are not pre-existent in the context.)
Zhāng：Zuó tiān nǐ kàn jiàn xiǎo dīng gēn xiǎo chén méi yǒu？
Zhang: Did you see Xiao Ding or Xiao Chen yesterday?
Lǐ：Xiǎo dīng，wǒ kàn jiàn le；xiǎo chén，wǒ méi yǒu kàn jiàn。
Li: I saw Xiao Ding; I didn’t see Xiao Chen.
(Ding and Chen have been mentioned by Zhang; therefore, they can be pre-posed by Li.)
 Yip, P. C., Rimmington, D., Xiaoming, Z., & Henson, R. (2009). Basic Chinese: a grammar and workbook. Taylor & Francis.
 Teng, W. H. (2016). Yufa! A practical guide to Mandarin Chinese grammar. Taylor & Francis.