Charlie learns from Eddie Van Halen, in a fantastic cameo, that the artist always brings a guitar into the bathroom in case he gets inspired. What's not explained is how his electric guitar produced such an awesome riff without an amp.
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Charlie and his studio friend, played by MadTV alumn Will Sasso, help Mia and her absolutely horrible voice record an album. Hey, anything to get in a woman's pants.
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Out with the old, in the with the new, as Charlie introduces his new fiancee, Chelsea, to his old, Mia.
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Charlie tries to help his ex-fiancee, Mia, start her singing career by lending his piano and musical contacts to her. Don't worry, Chelsea approves.
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Two and a Half Men Season 7 Episode 1 Quotes

Alan: You plan on kicking me out when mom dies?
Charlie: You plan on being here when mom dies?

Jake [about his sister]: So far she eats, she poops and she sleeps. I'm not impressed
Berta: Give her a bad hair cut and she'd be you
Jake: Excuse you, I paid $9 for this haircut
Berta: Sorry