Mitch and Cam host a "Lonely Hearts" party for their single friends. They wake up the next morning with massive hangovers and a mystery to solve: Dylan is living in their house and they have no memory of inviting him to stay. Notable Guest Stars

One Night Stand-off - Baby Daddy (Series 4, Episode 15) - ‎Apple TV

: His return is a highlight, especially his comedic song that left the cast struggling to stay in character during filming.

: Before his global music fame, the singer appeared in this episode as a musician. Interesting Trivia & "Blink-and-You'll-Miss-It" Moments

: She appears as Mitch and Cam’s wild party-girl friend who challenges them to a night out without "baby talk".

: In this episode, "Tater" is played by David Faustino , who played Bud Bundy (the son of Ed O'Neill's character Al Bundy) in the classic sitcom Married... with Children .

: Fans noted a continuity quirk where Dylan calls Mitch and Cam his "ex-girlfriend’s uncles," reflecting his on-again, off-again status with Haley at the time.

Phil and Claire's alter egos, Clive Bixby and Juliana , return for their annual Valentine’s tradition. However, the romance is cut short when Claire faints due to a genetic heart condition, landing them in the hospital.