The Tottenham star will play no part in the match but has remained with the Welsh players in Cardiff to help them prepare , despite being heavily linked with a move to Real Madrid and his efforts have prompted some kind words from Swansea City defender Williams.
"Fair play to him. I think with the situation he finds himself in, to turn up and to show his face, just be his usual self and get on with it," said Williams.
"We haven't really spoken about it too much, I'm sure he gets it from all angles but fair play for coming down the M4 and joining up with the boys."
Williams added: "Whatever decision he makes he's going to be that top star now.
"At the end of the day he's an exciting player, Gareth, he's a fan favourite. People come to watch him and it's great because we're there as well.
"The training session was funny yesterday, people climbing trees to try and get a glimpse."