Blake's ex-wife Miranda Lambert.
"She was not surprised to hear of the romance between Blake and Gwen. They were always pretty flirty," a source told E!. "Miranda and Blake were on the rocks on and off and knew that this could always be a possibility."
Although Blake may be moving on pretty quickly, the exes have maintained an amicable split, even speaking to each other on social media. E!'s source insists that Miranda only wants Blake to be happy.
"Blake is just a flirty kind of charmer," the insider shared. "She has nothing against Gwen and thinks she is a very talented artist. Whomever Blake is with she wishes them the best."
Romance rumors heated up over Halloween weekend when Blake and Gwen were seen cozying up at Maroon 5's Halloween party, just three months after Blake and Miranda split back in July.
For her part, Miranda is taking this time to better herself. E!'s source shared, "Miranda is at a point in her life where she is really focusing on herself and her music. This is a new chapter for her to create new relationships and really move on. Miranda has been going through many personal changes over the past few months, but it's all for the better."