The first round of group games get underway later.
Manchester United manager Ole Gunnar Solskjaer believes their summer signings have made them contenders to win trophies this season.
They begin their Champions League campaign later away to Swiss side Young Boys in Bern.
Cristiano Ronaldo, Raphael Varane and Jadon Sancho - who all joined in recent months - should feature.
Solskjaer says the squad's in a good place.
Kick off for their Group F clash is at 5.45.
Then from 8pm, holders Chelsea begin the defence of their title.
They have a home fixture against Zenit St Petersburg in Group H.
Elsewhere, Barcelona and Bayern Munich clash in Group E.
Weekend Local GAA & LGFA Results
Sunday Morning Sport: It's Another Busy Day In The Local GAA Championships
The Focus This Weekend Is On The UPMC Senior Hurling Championship And The Tom Cross Junior Football Championship
David Courell Appointed CEO of the FAI
The First FAI Cup Semi Final Takes Place Tonight
This Weekend's Local GAA & LGFA Fixtures
Kildare Trio Included In Republic of Ireland Squad
Famous Win For Aston Villa Over Bayern Munich In The Champions League
