An extract from Gillan's interview on knac.com (December 24th 2006):
KNAC.COM: Are you friends with David Coverdale and Glenn Hughes?
GILLAN: No. I know them, obviously, and I get on fine with them. I’ve only met David a couple times in parting. I’ve met Glenn a couple of times and I have great respect for him. He’s a great musician, a great singer. Glenn’s an extraordinarily talented man. But I wouldn’t classify them as friends because I didn’t develop any relationship with them because I was doing different things when they were in Deep Purple. And to be honest, that was a weird period anyway, because I take these things extremely personally and I get quite emotional about things. When I left the band I didn’t pay much attention to what Purple was doing—it’s like watching your ex-Missus making love to some other guy. That doesn’t turn me on.
http://knac.com/article.asp?ArticleID=5166