The 42-year-old, who has played for both the Bluebirds and the Swans during his long career, will be present at the encounter to witness what will more than likely be the last derby at Ninian Park before Cardiff move to their new stadium this summer.
And he believes the vociferous crowd in the Welsh capital will have a big part to play as the hosts look for three crucial points in their bid for promotion.
"As it's the last derby match at Ninian that really will add spice to the occasion," admitted Legg, who currently plys his trade in the Welsh Premier League for Llanelli.
"Both clubs are going really well, but I believe Cardiff will win it. Swansea will find the atmosphere intimidating. They will be up against the fans - and they are a factor.
"The Swans have had a tremendous season, but Cardiff are the side best equipped to go into the Premier League right now."