The ABC late-night host will be Maher's midshow guest. "Real Time" repeats at 11:30 p.m. Friday, which means that Kimmel will be in competition with himself. "Jimmy Kimmel Live" airs at 11:35 on WFTV-Channel 9.
Maher's roundtable guests will be playwright Anna Deavere Smith; gay political analyst Robert Traynham, who was an aide to Rick Santorum; and John Avlon, columnist for Newsweek and The Daily Beast and a CNN contributor.
"Real Time" is in its 11th season.
In other guest news, Celine Dion visits Katie Couric on "Katie" at 2 p.m. Thursday on WESH-Channel 2. Thursday is the first day of the May sweeps ratings period.
Dion's husband, Rene Angelil, will join them for the chat. Dion discusses her family, her fertility struggles and her husband's cancer diagnosis.
The singer will preview the title track from "Water and a Flame," her album that will be released in October.
Oprah Winfrey is a guest on "Steve Harvey" at 3 p.m. Friday on WFTV-Channel 9. She talks about hosting tips she has given Harvey, what she misses about hosting her daytime show and her plans for OWN, her cable channel.