“Margaret Thatcher was lovely,” he said.
“To be honest, I didn’t really like her until I met her.
“I was waiting for her outside at a function, and she said: ‘You must be freezing, come into the warm.’
“I didn’t expect her to be like that.”
In his 50 years collecting autographs and photos, Stewart has tracked down a staggering 10,000 stars.
But this year he has a big aim – to meet another 1,000 celebrities.
The 68-year-old retired bookkeeper, who doesn’t drive and travels the country by coach to hunt out famous faces, is currently at the 400 mark. He hasn’t even given himself a day off so far this year.
“I want to make it my best year ever,” he said.
“I don’t get bored, put it that way!”
This weekend Stewart went down to London for the Laurence Olivier theatre awards, where he was snapped with comedian Tim Minchin. Pencilled into his packed diary for the weeks to come are chances to meet One Direction, Mike Tyson and McFly among others.
His unusual hobby started when he would catch the stars at Batley Variety Club, but now, he said, meeting celebs is a totally different experience.
Many of the bigger names charge to sign their names or pose for photos, while autograph hunting is now no longer the preserve of enthusiasts like Stewart, but also online sellers looking to flog signed memorabilia.
“For me to get my photograph taken with Katie Price, I had to get her perfume, which cost £20 a bottle. I didn’t use it myself!”
Stewart, of Batley, has even joined Facebook, where he can share his photos with fellow enthusiasts and find out who’s met who.
“I love getting somebody that nobody else has got,” he said.
“Sometimes the bigger stars are nicer. Sylvester Stallone was great and John Travolta was smashing.”
Stewart is the first to admit he has an unusual hobby for a pensioner.
“People think I’m crazy. I’m 68 years old and I’m doing more and more when I should be slowing down. People ask, ‘How the hell do you keep going?’ I don’t want to be an average person. I don’t want to be an also-ran.”
PICTURE: Stewart with (clockwise from top left) Jennifer Aniston, Sylvester Stallone, Pierce Brosnan, Johnny Depp, Dermot O’Leary, Tilda Swinton and Jake Gyllenhaal.