With Pierre-Emerick Obameyang, 28, moving to Arsenal from Dortmund earlier today and Michy Batshuayi undergoing a medical with the Bundesliga outfit, the eternal triangle is completed.
Giroud joined Arsenal in 2012 as a replacement for Robin van Persie after the Dutch striker moved to Manchester United. A £12m deal for the leading scorer with then Ligue Un champions Montpellier, Arsène Wenger kept faith with the France international even during his frequent barren spells.
A product of the Grenoble youth academy, Giroud moved to Istres and Tours before Montpellier snapped him up.
His career has reached stratospheric heights, first with Arsenal and now Chelsea. The Blues are suffering problems in front of goal with Alvaro Morata and Michy Batshuayi both unable to find a consistent vein of form.
Giroud, with four goals in eight appearances, is in better form than both. However, he had three goals in his previous 17 games underlining the erratic nature of his own finishing.
The striker who scored 105 goals in 253 Arsenal appearances, turned down moves to Everton and Dortmund to move to Stamford Bridge. For Chelsea, his appeal is that he is not cup-tied for the Champions League with the Gunners featuring in the Europa League.