The figure illustrates a very plausible evolutionary scenario for ζ Puppis, a scenario that also reproduces the stellar parameters discussed in the present paper. A 60 + 50   M_⊙ binary with a period of 30 days formed initially in the Vela R2 cluster sinks to the cluster center due to mass segregation. After about 3 Myr, when both stars have transformed already a significant fraction of hydrogen in helium in the core, the binary encounters a 50   M_⊙ massive single star¹⁴. As a consequence of the dynamical interaction, the two binary components merge and the merger acquires a runaway velocity of 60–80 km s^-1 and will leave Vela R2¹⁵. About 1.5 Myr after the merger process, the resulting star has all the properties of ζ Puppis.