The venues and dates for the Carnegie Challenge Cup semi-finals have been confirmed by the Rugby Football League.
Wigan will play St Helens on Saturday 6 August at The Halliwell Jones Stadium, Warrington with a 1630 BST kick-off.
Wigan booked their place in Saturday's 44-24 win at Warrington, while Saints beat Hull KR 54-6 on Sunday.
Castleford face Leeds on Sunday 7 August at Keepmoat Stadium, Doncaster with a 1515 BST start. Both matches will be live on BBC2.
Castleford beat Huddersfield 22-18 in the quarter-finals, while Leeds overturned a half-time deficit to win 38-22 at Hull FC.
Saints, chasing an eighth Challenge Cup win in 16 years, are through to their 11th successive semi-final.
But record 17-time winners Wigan, who last won the trophy with a 21-12 victory over Saints at Murrayfield nine years ago, are favourites after ending Challenge Cup holders Warrington's hopes of a third straight win.
Warrington destroyed Leeds 30-6 at Wembley last August in front of 85,217 fans, the highest Challenge Cup final crowd at Wembley in 22 years.
But 11-time winners Leeds, whose last triumph was at Wembley in 1999, now have a chance to make an instant return.
They face a Tigers side against whom they earned their biggest win of the season, 48-6 at Castleford back in April.
It also means Leeds and Cas meeting two weekends running as they are due to play each other in the return Super League match at Headingley the following Friday night.