|Venue: Crucible Theatre, Sheffield Dates: 18 April-4 May|
|Coverage: Watch live on BBC TV, HD, Red Button, Connected TV, online, tablets, mobiles and BBC Sport app. Full details here.|
Mark Williams says he will approach the all-Welsh first round Crucible match with Matthew Stevens as if it is the last time he will play in the World Championship.
The pair meet in a repeat of the 2000 final which Williams won 18-16.
Speaking on the eve of the match, the 40-year-old said he planned to enjoy the clash with his "good friend".
"You've just got to treat it as if it could possibly be the last time you ever get here," he said.
"I'm going to enjoy it more this year because at the end of the day we're both not getting any younger.
"If you've got to go through the qualifiers and win three games, that's very difficult to do and I'm going to enjoy it just in case it is my last time here."
Williams claimed the first of his two World titles when he beat Stevens in 2000, following it up three years later when he beat Ken Doherty in the final - also by 18 frames to 16.
|An all-Welsh affair|
|Williams and Stevens have met 15 times since Williams beat his fellow countryman 18-16 in the 2000 World Championship final, with Stevens only winning on five occasions.|
The world number 14 failed to qualify in 2014, but is back after a one-year absence after regaining his place in the top 16 following a series of improved performances this season.
Stevens clinched his place at the Crucible with 10-5 win over Joe Swail. in the qualifying tournament.
Williams said he had difficulty believing that it is 15 years since he met Stevens in the final.
"It's been a long time now," he added.
"Matthew phoned me up to tell me I'd got him in the draw and reminded me it's 15 years now since we played each other here last and I couldn't believe it really.
"It made me feel old when he told me that."
Williams added that his friendship with Stevens - twice a beaten Crucible finalist - would not affect his approach to the game.
"I'd rather have drawn someone else, I don't want to meet a Welshman in the first round," he admitted.
"I try 100% in every game I'm not going to be trying any harder because Matthew's a Welshman I just play as hard as I can in every game and the opponent doesn't really matter because you shouldn't really play the opponent.
"Because we are good friends we'll probably be having a chat between frames, which you don't do against other players.
"But you can't try any harder because you're playing against a certain person."