South Park creator Trey Parker is set to become a first-time father.

The comedy writer has been dating his partner Boogie Tillmon for several years, and they live with her 11-year-old son from a previous relationship.

They are now set to welcome a new addition to the household as Tillmon is expecting the couple's first child together.

The brunette beauty showed off her baby bump on the red carpet in London on Wednesday at the press night of his hit show The Book of Mormon in the West End.

Parker, 43, was previously married to Emma Sugiyama, who he split from in 2008 after two years of marriage.