Olivia Wilde & Jason Sudeikis' Alleged Dog Walker Talks Losing Gordon

Olivia Wilde and Jason Sudeikis' dog walker is still reeling from the loss of Gordon, and speaking out about it for the first time ... saying there was no warning her time with the pup was ending.

Now, the L.A.-based dog walker's remaining anonymous, but says she was hired by Olivia and Jason in the fall of 2020. She admits being star-struck meeting Jason for the first time -- in a letter to Gawker she hilariously says, "I was suddenly willing to kill for him."

Interestingly she didn't have that reaction to Olivia, and in fact, never actually uses Olivia's name in the letter ... only referring to her as Jason's ex.

Seems she's chosen a side in the split! Anyway, she had an instant bond with Gordon.

She describes their walks together as "my happiest mornings during COVID's most depressing drawn-out flop era" ... but that all ended when she got a text that simply read, "No more Gordon walks."

She was pretty beat up over the news ... adding there was no reason given as to why their time together had to end. She says she only recently found out -- through the ex-nanny's allegations -- Gordon was dumped so OW could spend more time with Harry Styles, and rehomed ... allegedly with her NY dog walker.

As we reported, Olivia and Jason deny those allegations from their former nanny. Sources close to the couple told us their kids were pretty upset when he was given away, but so was everyone else.