Dylan McDermott and Dermot Mulroney act together for the first time when Mulroney guest stars on McDermott’s Fox comedy ‘LA To Vegas.’ In an exclusive joint video interview with USA TODAY’s Bill Keveney, the two find humor in the identity mix-up.
Robert Hanashiro, USA TODAY

LOS ANGELES – You say McDermott. I say Mulroney. After three decades in Hollywood, let’s finally call the whole thing on.

Dylan McDermott and Dermot Mulroney, linked together and sometimes mistaken for each other, are acting together for the first time in McDermott’s new Fox comedy LA to Vegas (Tuesdays, 9 ET/PT).

McDermott plays macho but insecure Capt. Dave, the pilot of a wacky weekend roundtrip to Sin City. Fittingly, in the comedy’s third episode, “Two and a Half Pilots” (airing Jan. 16), guest star Mulroney’s Capt. Steve arrives as a rival. Dave feels a bit intimidated by Steve, who flies international routes.

Although they have been sometimes annoyed at the fan confusion, famously parodied in a 2012 Saturday Night Live sketch, the actors are at peace with the mix-ups.  They chatted exclusively with USA TODAY while taping a second episode, to air late this season, in which the rivals are on the verge of — gasp! — a fistfight.

“This is the first time we’ve ever been in the same room together, proof that we are two separate people,” says Mulroney, 54, whose credits include My Best Friend’s Wedding and Shameless.

More: Dylan McDermott flies the zany skies in Fox’s ‘LA to Vegas’

They play the confusion for humor, with a touch of self-deprecation, as they apparently do when fans mistake them.

“It’s a pretty regular occurrence,” Mulroney says.

McDermott, 56, who starred on ABC’s Emmy-winning The Practice and showed off his comic chops in The Campaign, lets it roll off his back.

“We’ve gotten to the point where we just go with it. So, if somebody says, ‘I loved you in My Best Friend’s Wedding,’ (I respond), ‘Thank you very much.’ ”

The two had bumped into each other over the years,…