Gratuitous guest spots where the singer has to point it out so that you notice

I'm thinking of:
1. Rick James, Superfreak: "Temptations, sing!"
2. A Tribe Called Quest, Verses from the Abstract: "Yes, my man Ron Carter is on the bass"

Are there other examples of this phenomenon?

Thundercat introduces Michael McDonald on a track from the "Drunk" album, as if that were really necessary.

Take it to the Songs That X thread

Tommy Barbarella in the house

tons, stevie wonder introduces the jackson five (twice, i think) in "you haven't done nothing" just off the top of my head

1. Rick James, Superfreak: "Temptations, sing!"

Rod Stewart also said "Temptations, sing it one time" on "The Motown Song" (one of the dumbest songs ever)

Eddie Money: "Take Me Home Tonight" ("Just Like Ronnie Sang...!")

"Ladies and gentlemen Mr. Elton John!"

"Yo! Bloodhound Gang and Rob Van Winkle, together on THIS track"

that's kind of a funny example though since no one really knows him as "Rob Van Winkle"

I know :)

A sample more than a guess spot but, SHIRLEY BASSEY’s IN THE REAR SAYING PRACTICALLY WHAT I’VE BEEN SAYING MY WHOLE CAREER.

Not a guest spot, or gratuitous but....

I'm reminded of No Fun by the Stooges, where Ron Asheton's guitar begins soloing towards the end and Iggy says/sings:

I say c'mon Ron
C'mon and lemme hear you tell em
Lemme hear you tell em how I feel
I say c'mon lemme hear you
Tell 'em how I feel

"Blow Stay-eeve!"

even more entertaining when Scooter does this on "Behind the Cow" to introduce "Mr. Fatman Scoop!!" since Fatman Scoop's first two words are "Fatman Scoop"

perhaps more subtle, but The Knife 'you take my breath away': "i'm in the first row on your show.. in the first row of the First Floor Power show"

Billy Shears?

CMON JAMES!

"Slash!" - Lenny Kravitz, 'Always on the Run'

I have no idea if this really counts, since it's the guest artist mentioning it on the lead artist's song:

Oh Maria Maria
She fell in love in East L.A
To the sounds of the guitar, yeah, yeah
Played by Carlos Santana

Had to think of that Santana thing to, I hate that song and always found that bit sooo ridiculous, as Santana then proceeds to play a riff which is subjectively at a headache-inducing pitch, but also objectively really simple. Namechecking the player would suggest something far more spectacular, following it up with that riff seems to give him somewhat more credit than he deserves for it.

From one guest artist to another: "Joni Mitchell never lies"

Shanice: "Blow, Branford, blow."

Melle Mel on "I feel for you" - "Chakha Kahn, etc"

Was Billy Shears a guest of Sgt. Pepper's band, or a member?

Indeed, he was the founder, as I recall from the great Robert Stigwood film.

'Go' by Grimes and Blood Diamonds, whose sole contribution seems to be to say 'Blood Diamonds' in a low-key way near the end

“The Intro and the Outro” by the Bonzo Dog Doo-Dah Band is this thing times a million.

Though if Wikipedia is to be believed when the singer goes “Eric Clapton, ukulele” it really is Eric Clapton playing the ukulele.

... and Adolf Hitler is definitely on vibes, I'd recognize his playing anywhere.