Question: What Frank Loesser song was covered on Glee: The Music, The Christmas Album?

Context articles: Greenwillow
Hoop-Dee-Doo
Glee: The Music, The Christmas Album
What Are You Doing New Year's Eve?
Pleasures and Palaces
Señor Discretion Himself
Baby, It's Cold Outside
I Hear Music
Somebody Somewhere (song)
Praise the Lord and Pass the Ammunition

Greenwillow is a musical with a book by Lesser Samuels and Frank Loesser and music and lyrics by Loesser.
 The musical is set in the magical town of Greenwillow.
 It ran on Broadway in 1960.
"Hoop-Dee-Doo" is a popular song published in 1950 with music by Milton De Lugg and lyrics by Frank Loesser and released as a single by Australian children's band The Wiggles from their 2001 album "Hoop-Dee-Doo!
 It's a Wiggly Party!"
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Glee: The Music, The Christmas Album is the fourth soundtrack album by the cast of the American musical television series "Glee".
 The album was released on November 9, 2010 and accompanies the season two Christmas episode "A Very Glee Christmas", aired December 7, 2010.
 Dante Di Loreto and Brad Falchuk serve as the album's executive producers.
 Critical reception has been mixed, with the majority of professional reviews praising the cover version of "Baby, It's Cold Outside" performed by Chris Colfer and guest star Darren Criss, as well as the vocals of Lea Michele and Amber Riley, but questioning the arrangements of some other tracks.
 The album debuted at the top position of the "Billboard" Soundtracks chart, as well as peaking at number three on the "Billboard" 200.
"What Are You Doing New Year's Eve?"
 is a popular song written in 1947 by Frank Loesser as an independent song—not written for a particular movie or musical.
 It first charted for The Orioles, peaking at No. 9 on "Billboard"'s Best-Selling Retail Rhythm & Blues chart in December 1949.
 Other charted versions include Danté & The Evergreens (No. 107 on "Billboard"'s Bubbling Under Hot 100 Singles in December 1960) and Nancy Wilson (No. 17 on "Billboard"'s Christmas Singles chart in December 1965 and No. 24 on the same chart in December 1967).
Pleasures and Palaces is a musical with a book by Frank Loesser and Sam Spewack and music and lyrics by Loesser.
 It is based on Spewack's flop 1961 play "Once There Was a Russian" and takes its title from the opening lyrics of the 1823 song "Home, Sweet Home": "Mid pleasures and palaces though we may roam, Be it ever so humble, there's no place like home."
Señor Discretion Himself is a musical with book, music and lyrics by Frank Loesser, adapted from the short story of the same name by Budd Schulberg.
 It was never completed before Loesser died in 1969, but it was revised and "completed" in 2004, with a new libretto by Culture Clash, vocal arrangements by Brian Cimmet and directed by Charles Randolph-Wright.
"Baby, It's Cold Outside" is a song written by Frank Loesser in 1944.
 It is a call and response duet in which one of the singers (usually performed by a male voice) attempts to convince a guest (usually performed by a female voice) that they should stay together for a romantic evening because the weather is cold and the trip home would be difficult.
"I Hear Music" is a popular song composed by Burton Lane, with lyrics by Frank Loesser for the Paramount Pictures movie "Dancing on a Dime" (1940).
 In the film it was performed by Robert Paige, Peter Lind Hayes, Frank Jenks and Eddie Quillan.
"Somebody Somewhere" is a popular song written by Frank Loesser.
 The song was published in 1956 as part of Loesser's musical "The Most Happy Fella".
"Praise the Lord and Pass the Ammunition" is an American patriotic song by Frank Loesser, and published as sheet music in 1942 by Famous Music Corp.
 The song was a response to the attack on Pearl Harbor that marked United States involvement in World War II.