Kelly Ripa missed out on Michael Strahan explaining why he's leavingLive! With Kelly and Michael after four years.

Saturday Night Live alum Ana Gasteyer stood in for Ripa, 45, who did not show up to co-host with Strahan on Wednesday morning. The former NFL pro told the audience that his last day on the show will be in September, as he's accepted a full-time position at Good Morning America.

WATCH: Michael Strahan Shows Plenty of PDA With Bikini-Clad Girlfriend Kayla Quick During Sexy Vacay

A source close to Live! tells ET that Ripa was not planning to take Wednesday off, but was "blindsided" by the news that Strahan was leaving. According to the source, Ripa may also take the rest of the week off.

ABC announced Strahan's departure on Tuesday afternoon, and he joked that some reports made it seem like he had died. "It is the same channel. I am not going anywhere," he insisted, adding that he plans on returning as a guest co-host. "I consider myself to be a part of this family."

Strahan went on to express his gratitude to those who've watched him on Live! "You still continued to give us your eyeballs, and watch this show," he said. "Thank you guys. I couldn’t have asked for better fans at all. You guys have been absolutely amazing. On top of that, I have worked with an incredible staff here."

WATCH: Regis Philbin Says He Hasn't Spoken to Kelly Ripa Since He Left the Show

Looking off camera at someone who works on the show, he added, "Don't cry or you're gonna make me cry!"

Strahan reiterated, "I’m not going anywhere. We still got months to go!"

WATCH: Kelly Ripa Gets Drunk and High in Totally Unexpected, Hilarious Broad City Cameo

At the end of the show, Strahan also took some time out to personally thank his longtime co-host. "I didn't want to say it earlier, but I really want to thank, of course, Kelly Ripa, because Kelly welcomed me here and I've learned so much from her," he said. "She's just been an amazing influence on me, and this has truly changed my life to be here with her."

He added, "Kelly, I thank you, I love you, and everyone else here at Live! I'm not going to cry on TV, mama, but everybody, thank you guys so much."

Ripa has yet to comment on her co-host's departure, but ET has learned exclusively that Anderson Cooper, Andy Cohen and Neil Patrick Harris are in the running to replace the 44-year-old TV personality. Here are more details on the Live! shake-up: