According to Jain tradition, Bhagwan Vasupujya’s immediately previous birth (just before he was born as a Tirthankar) was:

• As a deva (celestial being) in Prāṇat Dev-lok,

Before that, an important earlier human birth mentioned in Jain granths is:

• King Padmottar (Padmottara Rāja), a righteous and spiritually inclined king who later accepted dīkshā.

So, in short:

• Last birth before becoming Tirthankar Vasupujya: Prāṇat Deva in Prāṇat heaven.
• Notable earlier birth: King Padmottar.

Both Digambar and Shvetāmbara accounts agree on the general pattern: human (King Padmottar) → celestial (Prāṇat Deva) → Tirthankar (Vasupujya Bhagwan).