Bottas was one of the stars of qualifying on Saturday evening as he charged to sixth place on the grid, making him the top qualifier outside the ‘big three’ teams.
It means the Finn will start on the third row of the grid alongside Hamilton after the Mercedes driver could only muster fifth, trailing both Ferraris and both Red Bulls.
Bottas also out-qualified his replacement at Mercedes, George Russell, who ended up ninth.
“We're starting side by side, it’s pretty cool,” Bottas said, when asked about lining up next to Hamilton.
“I just saw him and we were both smiling. It should be fun.
“If somebody had told me in Bahrain we’re going to be starting side by side with Lewis, I’d take it.
“But yeah, this is the beginning, the starting point for our journey. Now we need to make sure we’re looking ahead and trying to look forward rather than backwards. So it’s exciting.”
Bottas also said it was “pretty cool” to have out-qualified the car he got out of at the end of last season, and joked that he was yet to talk to old boss Toto Wolff: “Not yet, I don’t have my phone. I’ll go and see him!”
The result marked a huge boost for Alfa Romeo after two difficult seasons where it fell away from the main midfield teams, slumping to ninth in last year’s constructors’ championship.
Bottas joined from Mercedes on a multi-year deal, and admitted that he took heart from the fact he had started so strongly in Bahrain qualifying.
“It is the first session that we would find out where we actually are,” Bottas said.
“Yes, it makes me happy. It gives me a lot of hope - instead, if I would have finished P18, it would have been a slightly bigger mountain to climb.
“It’s still a mountain, but it’s not Mount Everest any more.”
Bottas said he knew qualifying inside the top 10 was within Alfa Romeo’s sights after how practice went on Friday, but admitted sixth was still “a bit of a surprise”.
He also revealed he used his streak of 101 Q3 consecutive appearances as added motivation for Alfa Romeo: “I told the team this morning that it’s time for 102 today, and they were all up for it. So yeah, it’s nice.”