Sian beat Phoebe and other nominees to win Female Performance In A Comedy during the surreal event, which saw winners and nominees forced to appear from home over video link.
She revealed they had been watching the ceremony together, but had to separate when they both had to call into the show to find out who’d won.
Speaking after her win, Sian told the press: “There was sound feedback so we broke into our friend’s house down the road.
“We reunited after I won and she gave me the godmother statue, we both have one.”
The sculpture, of the naked torso of Fleabag and her sister’s late mother crafted by their godmother, is a fixture in the show.
Sian said she and Phoebe – who she has been friends with for over 20 years – had been “stuffing their faces” with vegan burgers during the ceremony as they “saw off the show”, which came to a conclusion with its critically-acclaimed second series.
Snagging your BAFTA for Female Performance in a Comedy Programme from the comfort of a beautiful garden? Well, that's just how @SiansUniverse rolls! #VirginMediaBAFTAs #BAFTAs pic.twitter.com/wbLytP0tTL— BAFTA (@BAFTA) July 31, 2020
She added: “There is so much history with this show, with my friendship with Phoebe.
“We have just championed each other since that day and I just feel so lucky to have found her and have somebody who believes in me more than I believe in myself.”
This article originally appeared on HuffPost UK and has been updated.