On Thursday evening the 31-year-old was unveiled as the Blues’ first signing of the summer, penning a two-year-deal at PO4.
It marks an emotional homecoming for the midfielder, who rose through the ranks with his boyhood club at the start of his career.
Pompey had to fend off interest from the Robins and Derby to land their former academy graduate as Danny Cowley’s summer rebuild begins.
Following the announcement, the Fratton faithful took to social media to express their delight in the Blues' maiden signing of the window.
Here is the best of the reaction from Twitter.
@keariss: I am well excited to see Pack back in a Pompey shirt!! Real statement signing this!!!
@Jake_PFC: Our midfield options are genuinely ridiculous for this level, get the attack sorted and we’re walking the league!
@HarvMarksy: This is huge by the way. Exactly the player we need. Leadership, experience and ability. Our midfield options with him, Morrell, Thompson & Tunnicliffe are superb for League One.
I can finally stop signing him every year on Football Manager.
@MarkRoser9: Top signing! Him and Joe and Louis in midfield is a top midfield and we will win the league by November.
@Len87668696: A good start! And great to have one of our own back, I'll stop moaning about lack of signings now for at least a week.
@PompeyPedro: First genuinely quality player with proper Championship pedigree we’ve signed on a permanent for absolutely ages.
Big signing. Big statement.
@CanadaPompey: Welcome home! Let's hope this is finally the start of a few decent signings.
@PORTSMOUTHFCLEE: I’m buzzing with this. Good work!! Let’s not stop there though!!!
@AntCoombes80: Pack, Morrell, Thompson, Tunnicliffe....not bad options for the middle of the park.
Can any of them play right back or up front?
@ivan_prothero: I haven’t been this excited about a signing since John Marquis, hope that isn’t a sign…
An absolute Championship quality midfielder added, let’s build on this.